"Two Parter: Part One" is the seventeenth episode of Season 3 of Teen Titans Go! and the one hundred and twenty-first episode overall. It first aired on 25 November 2015 on Cartoon Network alongside "Two Parter: Part Two".
The Titans visit the Hall of Justice to use the pool, but then decide to check out the inside.
Robin tells the Teen Titans that it's going to be a special day which will take up twice the amount of a usual adventure. The Titans are unsure when this special adventure will start as Robin claims that the air conditioner breaking is the start to their special. Beast Boy says he's starting to feel hot and Robin takes him out of the tower and into the pool. They are joined by the others, but Starfire says that it still doesn't feel special to her. Cyborg performs a cannonball, but accidentally destroys the pool. Beast Boy, still feeling hot, says he knows a special place where they can cool off, and takes the Titans to the Hall of Justice.
Robin, Beast Boy, Raven, and Starfire enter the fountain, but Cyborg tells them they're disrepecting it with their horseplay. He explains that he always wanted to join the Justice League and he's worried that if they caught him swimming in their fountain, they wouldn't let him join in the future. Robin mocks Cyborg's dream by claiming that the Justice League would choose him over Cyborg and tells him to get into the fountain. He swims by Beast Boy and finds a warm spot. Raven quickly realizes what the warm water is and stops Starfire from swimming over to Robin and Beast Boy, saying that they should exit the fountain. Robin agrees and decides to introduce Cyborg to the Justice League so that he may fulfill his dream. However, he presses the doorbell and hides with Beast Boy, Raven, and Starfire as part of ding dong ditch. Cyborg becomes nervous, but no one answers the door. Robin deduces that none of the members are home and offers a tour of the inside. He finds a key under the mat and the Titans enter the Hall of Justice.
Robin claims that visiting the Hall of Justice is special, but Raven reminds him that nothing's happening. However, Cyborg and Starfire disagree as they feel inspired. Robin asks what part of the Hall of Justice they want to see first, disappointing Cyborg when they choose to see the refrigerator. Raven notes how much yogurt Wonder Woman stocked on the fridge while Beast Boy calls dibs on a sandwich. Robin stops him from eating it, showing him that the sandwich belong to Batman. Beast Boy transforms into a bee and stings Robin's hand, causing him to drop the sandwich. He takes a bite out of it and activates an alarm that summons a sentry robot, who scans the Titans and notices they're not Justice League members. It chases them throughout the Hall of Justice until Cyborg and Raven use their pool supplies to distract it.
Cyborg leads the Titans into a closet and tells them to suit up as a member of the Justice League in order to trick the sentry robot. Raven claims that they're not going to be able to fool the robot by dressing up in the Justice League's costumes, but calls dibs on Batman. Robin, Beast Boy, and Starfire express interest in dressing up as Batman, but Raven says she already called dibs and puts on his cowl. However, they are disgusted by how sweaty the cowl smells, but Robin puts it on anyway. Cyborg gives Beast Boy Martian Manhunter's costume and has Raven dress up as Wonder Woman. She scoffs at the costume until Cyborg tells her that the rope is the Golden Lasso and those bound by it have to tell the truth. Raven uses the lasso on Robin, forcing him to admit that the wet spot on his suit was urine. Cyborg dresses up Starfire as the Flash and puts on a Green Lantern power ring, becoming Green Lantern. He claims that the ring is the most powerful weapon in the universe and demonstrates its power by summoning the Golden Girls. Robin mocks Cyborg's choice and he recalls them when the sentry robot attacks the closet.
The sentry robot enters the closet and repeats that only Justice League members are allowed. Cyborg claims that they are the Justice League and the sentry robot scans Raven, welcoming her as Wonder Woman. It scans Cyborg, but is unable to process his identity. Cyborg claims he's Green Lantern and the robot asks for which Green Lantern he is as there are several, outraging Cyborg. He claims that he's Steve, but the robot informs him that there are no Green Lanterns by that name and attacks the Titans, save for Raven. Cyborg asks for her help, but she claims she never heard of her and decides to eat one of her yogurts. The sentry robot corners the Titans and Robin mocks Cyborg's poor leadership, citing it as another reason the Justice League would choose him over Cyborg. Starfire bids good-bye to her dear friends, giving Cyborg an idea. He uses the power ring to summon the Golden Girls to attack and they destroy the sentry robot.
Raven reunites with the Titans in a lounge and asks how the fight with the sentry robot went which Cyborg says was awesome. Robin tells the Titans that he was right about the day being special. Starfire agrees with him, but notes that it took the same amount of time as their other adventures. Suddenly, the computer displays a message that the Justice League has been captured by Darkseid. The Titans gasp, and Robin restates that their special adventure has another part.
For a full transcript of "Two Parter: Part One", click here.
Running Gags: Robin saying special and that he should be the one who gets to join the Justice League.
Food Content: The Titans vote to see the fridge first which has Wonder Woman's yogurt and Batman's sandwich.
Starfire tells Robin that they already experienced their air conditioning breaking which Cyborg says took trouble filling up a normal amount of time, referencing "Hey Pizza!".
The sentry robot clams it knew Raven was Wonder Woman, because of her legs, continuing the running gag of Raven's legs first established in "Legs".
This episode contains references to the Justice League of America:
The Teen Titans visit the Hall of Justice, their headquarters.
The Titans dress up as Justice League members, including Batman, Wonder Woman, The Flash, Martian Manhunter, and Green Lantern.
Cyborg wanting to join the Justice League is meant to reference the DC Extended Universe's Cyborg, who is interpreted a founding member of the team.
Brainiac's head, Doctor Fate's helmet, The Flaming C's oven mitt, Doomsday's skull, the bottled city of Kandor, a mask worn by Immortan Joe in Mad Max: Fury Road are displayed at the entrance of the Hall of Justice.
Red, green, and blue Kryptonites are destroyed by the sentry robot when it is chasing the Teen Titans.
Bea Arthur as Dorothy Zbornak, Betty White as Rose Nylund and Rue McClanahan as Blance Devereaux from 1985-92's The Golden Girls are used by Cyborg as a projection from the Green Lantern power ring.
In "Hey Pizza!", Raven claims that her cloak is her bathing suit, but she uses a strapless one-piece bathing suit when she goes swimming.
The Image Gallery for Two Parter: Part One may be viewed here.