Only Human is the 17th episode of the Teen Titans series and the 4th episode of season 2.
The episode starts with all the Teen Titans training in the gym. Starfire and Robin do combat exercises, Raven meditates and focuses her energy, Beast Boy professes his changing ability in a run pad and Cyborg tries weightlifting. He has a gadget which shows him how much of his power he used already. He tries to give more then 100%, he really goes for it, but he fails...
Cyborg is very angry about this situation, because in the past he was an athlete and he always tried to exceed his limits, and he always succeeded, reaching 110% of his body's strength, but now he feels he can't do this anymore since he is half-robot and he has limits that are built-in to his robot body.The others (even Raven) try to cheer him up, but he just wants to be alone. He sits down to play an online game, and he ends up beating the best player, Atlas. Atlas then demands a rematch. Cyborg doesn't know what this means and accepts the challenge. Atlas, a giant robot, appears in front of Titans Tower and fights him straight away.
The Titans rush out to help Cyborg but Atlas defeats them all. The villain then captures all the other Titans and Cyborg must face him alone in order to rescue them. Cyborg trains as hard as he could and then meets up with Atlas in the city's Old Stadium. Atlas has a mechanic, Spike, who help keep him in good condition and equips all his weapons for him. Atlas always taunts Spike and treats him badly, even though Spike is devoted to him. Despite training hard, Cyborg loses and runs away, leaving his friends behind. Cyborg keeps commenting that his limits are built-in as he is half-robot; he cannot train harder—all he will ever get up to is 100%. Eventually his conscience tells him that his human half is what can help him defeat Atlas, not his robot half. Cyborg returns to the Old Stadium and has a rematch with Atlas. During the battle, Robin tries to convince Spike that Atlas has been horrible to him, that he should do a good thing ,and that he should leave Atlas' service.
Cyborg continues to fight, but he once again only reaches 100% of his strength. Atlas easily overpowers him, but Cyborg is still determined to win the battle. Spike, finally realizing the truth of Robin's words, frees the captured Titans and along with the Titans, cheers on Cyborg. Cyborg, with the strength of his friends' support and his own human half, breaks his limiter and reaches 110% plus (or only 110%) of his strength, which allows him to finally defeat Atlas.
- Atlas: No more. I am defeated. You are a better robot.
Cyborg: No, I'm a better person.
- Starfire: Your Atlas is nothing but a Zolworg Tubeck Plixing Zarbmarker!
Beast Boy: Yeah, what she said!
- The name of the person from East Gotham City that Atlas defeated in the video game was named after Derrick J. Wyatt, the character designer of Control Freak and I.N.S.T.I.G.A.T.O.R..
- This episode bears some resemblance to the 1976 movie Rocky, as Cyborg must beat Atlas, who could be a homage to Apollo Creed, who coincidentally, was also named after a greek deity.
- It may also be a reference to the 1982 movie Rocky 3, as Cyborg lost his first match against Atlas, similar to how Rocky lost to James Lang, but after gaining a new confidence, they are able to defeat their respective rivals.