The relationship between Archie Andrews and Jughead Jones is complicated and pre-dates the series. They were best friends up until a falling-out in the summer of 2017 after Archie canceled their road trip at the last minute. Their relationship improves over the course of the first season until Archie admits to investigating FP's trailer.
Archie and Jughead were best friends since childhood. Fred recalled Archie sneaking out at night to go to Jughead's treehouse.
They were supposed to go on a road trip over the weekend of July 4th, but Archie cancelled at the last minute to hook up with Geraldine Grundy, with whom he was having an affair. Sometime afterwards, Jughead and Archie got into a serious fight that disrupted their friendship. They lost touch and never attempted to make up, and their first conversation since the fight is a tense encounter after Archie runs into him at the Chock'lit Shoppe while looking for Betty.
After Archie and Veronica kissed at Cheryl's after party, Archie went looking for a heartbroken Betty to apologize, which led him to Pop's Chock'lit Shoppe where he found Jughead, sitting alone. Archie awkwardly walked over to his old friend and asked to sit in the booth with him. They talked about Jason's death and Jughead gave him a piece of advice, to just talk to Betty because it could go a long way; it would have gone a long way with him.
At school, Jughead had a brief conversation with Archie in the hallway, where his sardonic humor over Jason Blossom's death fell short with Archie. Before heading off to class, Jughead recalled that he and Archie were supposed to go on a road trip during the summer, over July 4th weekend, which was the day Jason was thought to have been murdered. Archie happened to bail on at the last minute, which led Jughead to believe that Archie was hiding something.
Jughead found out what Archie was hiding, when he discovered Archie was having a secret affair with his music teacher, Ms. Grundy. He stumbled upon them as they were in a close embrace, leading Jughead to confront Archie later that day at the Andrews house. Archie revealed that he and Ms. Grundy had been in a relationship since the summer and that they were both at Sweetwater River on July 4th, when Jason was ostensibly killed. They heard a gunshot that day, which Jughead urged Archie to report to the police, but he resisted, having been manipulated by Ms. Grundy into keeping this information to himself for fear their relationship would be discovered. Jughead claimed that she cared more about herself than she did Archie, the fact that she was the one who told him to keep quiet only supported Jughead's claim. Scared that Jughead would reveal his secret, Archie began to threaten him, but Jughead cut him off, wondering what exactly he would do. Before he left, Jughead remarked that although the Archie he used to know wasn't perfect, he at least tried to do the right thing.
Despite the rift between them, when Reggie Mantle began picking on Jughead in the school lounge, accusing him of being Jason's killer, Archie immediately stepped up to protect his friend which resulted in a fistfight with Reggie. Jughead tried to help Archie by separating them, however, he was grabbed by one of the other football players, preventing him from stopping the fight and had to watch as Archie was knocked out.
Archie later approached Jughead at the annual fall Pep Rally to inform him that he would be taking his knowledge of the gunshot to the police. Archie then apologized for the stuff he had said to Jughead the previous night. Jughead accepted his apology, which marked the beginning of them rebuilding their fractured friendship. To celebrate, they headed to Pop's Shoppe for milkshakes, where they ran into Betty and Veronica, who welcomed the boys to join them.
Jughead was seated in a booth with Betty, Veronica, and Kevin at Pop's when Archie entered the diner with his father and Ms. Grundy. Betty immediately went to speak to Archie, as she had recently found out about Archie's affair with his teacher. Jughead hid low in his booth as Archie asked Betty if Jughead had been the one to tell her, though he hadn't, she had figured it out on her own. The next day at school, Archie asked Jughead how hard it would have been for a heads-up, and if Betty would be writing about him and Grundy in the paper like she did with Chuck Clayton. Jughead explained that not getting involved in the situation with him, Betty and Ms. Grundy was the most moral, apathetic choice he could've made. He also mentioned that Archie had nothing to worry about, as Jughead assured him that Betty would "never do anything that could possibly hurt him - probably". He then asked Archie what he saw happening long-term with Ms. Grundy, what Archie wanted out of it. Archie stated that he wanted to be with her for as long as he could, and asked Jughead to warn him if Betty did decide to do something about his secret.
Archie later discovered that ver since the closing of the Twilight Drive-In, Jughead had been living out of a forgotten closet under a staircase at the High School. Jughead explained that things weren't good at home, and that his dad had fallen off the wagon after Fred Andrews fired him from Andrews Construction, and his mother had left with Jellybean to live with their grandparents a while back. Archie invited him to stay at his place, but Jughead declined, asserting his situation was only temporary. He also insisted that Archie not tell anyone, especially not Betty, which perplexed Archie. Later on in the student lounge, Archie noticed a moment shared between Jughead and Betty and was taken aback and a bit jealous.
Afterward, Archie caught up with Jughead and confronted him about the comment he had earlier made about not telling Betty about his living situation. Archie surmised that this was due to the fact that Jughead and Betty were now a couple, and Jughead admitted there was something between him and Betty. Archie said it was cool then quickly changed the subject. He had stated that he had spoken to his father about Jughead's situation, and Fred was willing to give Jughead's father another chance, but only if FP wanted it. Archie thought it would be a good idea if Jughead went to talk to FP as well. After he did, FP accepted Fred's offer.
After a long first day back at work, Archie and Jughead suggested they celebrate with a dinner at Pop's Chock'lit Shoppe, where the two fathers reminisced about their youth, much to the amusement of their sons. Later that night, FP, Jughead, and Archie practiced playing music in the garage at the Andrews house. Before the Joneses left Archie wanted to know what had happened between FP and his father, and FP explained that Fred forced him to resign after he took up some odd jobs in order to provide for his family, which eventually landed him in jail. Fred was kind enough to bail him out, but at that point, Fred wanted to part ways. Shocked, Archie went and confronted his father who claimed that FP had been stealing from the company and selling things on the side, and all things considered, Fred believed he was being generous. He gave FP numerous chances, bailing him out of jail countless times, but when someone was drowning, Fred didn't believe you could save them if they were going to drag you down with them. However, Archie didn't believe it was fair for Jughead to drown too.
The next morning, Jughead was taken into custody and brought down to the Sheriff Station by Sheriff Keller, as a suspect in Jason's murder. He and Betty’s fingerprints were found on Jason’s torched car that they had previously discovered, which was expected. However, Jughead had a surprising juvie record from six years prior when he almost burned down Riverdale Elementary School which, according to Jughead, was an accident - he had just been playing with matches. Fred and Archie came to his aid, and Fred told Sheriff Keller that Jughead was working for his construction company on July 11th, which led to the Andrews later falsifying a time-card to prove. Jughead’s father showed up at the station just as everyone was leaving and caused a scene in front of Fred, Archie, and Betty. Jughead convinced him to let it go, and Archie once again extended an invitation for Jughead to live with him, until FP sorted himself out. In the end, Jughead went to live at the Andrew’s house and Archie apologized about how things went with their fathers.
After a late night of gaming, Fred entered Archie's room to inform the boys that it was time to call it a night, as he would be breaking ground on the SoDale project early the next morning. He asked Jughead how he was settling in, and Jughead compared himself and Archie to college dorm mates.
. Come morning, Fred had been abandoned by his crew, who had been lured away by Cliff Blossom in hopes of halting construction. Archie, Jughead, Kevin, and Moose Mason volunteered to aid Fred in keeping the SoDale project on schedule until he could find a real crew. Jughead commented how handy Archie was with a wheel barrel, joking that if his music career never paid off, he could always have manual labor as a fallback. As the day came to an end, the boys returned to the trailer. However, Moose realized he had forgotten his phone back on the project site. As he went to retrieve it, he was ambushed by two thugs, who warned them to stop construction or else they'd be back. While Fred thought that Cliff Blossom was at the center of the attack, Archie speculated that it could've been the Southside Serpents, who were angry due to being kicked off their territory. Jughead than reminded everyone that the Serpents never bothered him when the drive-in was still up and running.
The next day, Archie found Jughead with Betty and Veronica at Pop's, and asked for Jughead's help as he, Moose and Kevin planned on finding the supposed Serpents that attacked Moose. Kevin's boyfriend, Joaquin, who was also a Serpent, could get them into the Whyte Wyrm - a known hangout for the gang. They planned to find Moose's attackers and notify Sheriff Keller. However, Jughead insisted that going to the bar was a terrible idea, but all Archie wanted to know was if Jughead would back him up. Jughead stated that he wouldn't, and Archie left angry.
At the bar, Archie did not find the assailants but instead found Jughead's father, leader of the Serpents, and realized that was the reason Jughead didn't want Archie going to the bar. Angry at being lied to, Archie unexpectedly crashed Polly Cooper's Baby Shower and confronted Jughead, who tried to calm Archie down claiming he could explain everything. Archie didn't want to hear it and revealed Jughead's secret to Veronica and Betty. Veronica told then to stop, to settle their fight another time as it was Polly's day, and escorted Archie out. Later that night, Jughead returned to the Andrews house, where he admitted that he should've trusted Archie, but he was afraid that his father was at the center of the attack. Archie understood where Jughead was coming from, saying that they were brothers and that they would always be there for each other.
Days later, in the student lounge, Archie announced to the group that he could be attending an exclusive summer music program with the help of the Blossoms. Jughead questioned their motives for doing so, and Archie explained that all he had to do was escort Cheryl to her family's maple tree tapping event. However, Jughead did not think it was a good idea to be getting involved with the Blossoms, asking if Val was cool with him being a Gigolo. Archie disagreed, and explained that if he wanted to succeed with his music, he had to make connections outside of Riverdale. Jughead, Archie, and Fred ate dinner together a couple night's later, after Archie had attended the Blossom event. They were momentarily joined by Cheryl, who dropped by to gift Archie with an expensive guitar as thanks for agreeing to escort her to a second event, which Jughead referred to as Archie pimping himself out.
After attending the second event, Archie finally realized what everyone meant about him not getting involved with the Blossoms. He went to see Jughead and Betty at The Blue and Gold offices and revealed a conversation he had overheard between Cliff and Penelope Blossom the night before. He revealed that Clifford Blossom might have been responsible for sending Hiram Lodge, Veronica's father, to jail. Jughead remarked that perhaps Hiram had taken his revenge by killing Jason Blossom, and added Hiram's name to their murder board.
For the last few years, on Jughead's birthday, he and Archie would go to the Bijou for a double-feature, it became their tradition. However, since he had a girlfriend this year, Archie thought it should be Betty who accompanied him to the movies. She agreed and thought they should throw Jughead a surprise party as well, as she had been told by FP that he had never had a party before. Veronica and Kevin thought it was a great idea, but Archie, didn't think so as he knew Jughead hated his birthday. He eventually went along with the plan, even offering his house to host the party, stating that it would be epic.
After school, Archie informed Jughead that this year Jughead would be going to the movies with Betty this year. Jughead became a little upset that Archie had told her about his birthday, to Archie wondered why, exactly, he hated his birthday so much. Jughead explained that it was leftover from when he was a kid. His home life wasn't that good, usually on account of his father, and he found pretending everything was great one day of the year very meaningless and just made him feel lonely.
The next night, Archie, Veronica, Kevin, Joaquin and Ethel surprised Jughead as he returned home from the double-feature with Betty. Regrettably, Jughead was less than thrilled about his party. Just when Jughead thought the night could not get any worse, the doorbell rang and the entire school was at the front door, led by Cheryl and Chuck Clayton, all ready to party. Despite knowing Jughead was upset, Archie let everyone in, causing Jughead to angrily walk away. He had retreated to the garage with the Andrews dog, Vegas, where he was later found by Archie. Jughead confronted him, of the opinion that it was Archie's responsibility to ensure that a party like that never happened on his birthday. Archie, however, told him it was Betty's idea and he had just gone along with it. While a party like that was not Jughead's style, Archie informed him that since he was Betty's boyfriend he would be getting the party whether he wanted it or not.
The morning after, Jughead was having breakfast while Archie cleaned up the mess from the party. Jughead teased him about Veronica, who he had seen come out of Archie's room earlier. Archie began to ask him not to say anything before Jughead cut him off and promised he "wouldn't be telling anyone anything, literally ever".