How Long Is Forever? is the 14th episode of the Teen Titans series and the first episode of Season Two.
One morning, Starfire intends to celebrate a traditional Tamaranean holiday, Blorthog, the Day of Friendship, with her fellow Teen Titans, but she finds them bickering over trivial things. She warns them that if friends do not value their friendship, "Rekma," or "the Drifting Apart" would occur, and result in the death of close friendships. The Titans reassure Starfire that this was perfectly normal behavior, and they would always remain friends. However their conversation is cut short when the alarm sounds, and the Titans rush off to their mission.
At the technological museum, a time-travelling villain calling himself Warp, attempts to steal a valuable clock. The Titans engage him, but Warp's knowledge of the Titans and his futuristic weapons fend them off easily. As he opens a time portal to return to his time one hundred years in the future, Starfire impulsively charges him and both vanish into the time-stream. As they are adrift, Starfire rips off a lens from Warp's chestplate; this results in both of them suddenly dropping out of the time-stream.
To her astonishment, Starfire finds herself in the middle of winter, and before her stands Titans Tower, decrepit and crumbling. As she investigates the structure, she encounters Cyborg as its only occupant, who has also fallen into disrepair and is now hooked to a bulky power generator. He reveals to Starfire that she is now twenty years in the future; the Titans have disbanded following her disappearance and gone their own ways. Starfire assumes that this is due to Warp's tampering with the time continuum and decides to seek out the others. In the course of her search, she finds a bald Beast Boy carving out a miserable existence as a carnival curio, and learns Raven has gone insane from loneliness, thinking that all around her is just an illusion.
As she tries to find Robin, Starfire encounters Warp again, who has also aged due to her theft of the lens, which is actually a vortex regulator, the heartpiece of his time-travelling technology; he demands it back to enable himself to return into his own time. When Starfire demands that he restore her past, Warp replies that nothing can be changed as the course of past, present, and future is inevitable. He takes back the vortex regulator, but before he can finish her off, he is attacked and forced to retreat. Starfire's defender turns out to be Robin, but with a new super identity: He now goes under the name of Nightwing.
In his hideout, Nightwing re-encourages Starfire by the fact that the Titans have always prevailed even against the impossible before and may do so yet again. With an old Titans Communicator he had kept, he alerts the other Titans, then he and Starfire proceed to the tech museum where it all began. Warp is already there reattaching the regulator to his chestplate, but before he can escape, Nightwing and Starfire attack, gradually joined by the other Titans. This time, Warp's weapons are ineffective as the Titans are wise to his tricks; a bullseye hit by one of Nightwing's birdarangs on the already damaged regulator causes the device to go haywire, reducing Warp to an infant. Cyborg uses the regulator to open a portal into the past for Starfire, and with a last happy look at her reunited friends and the stolen clock in her hands, she steps through the portal and reappears in the museum with the clock, proving that Warp's theory was wrong.
After telling the others about her adventure in the future, the Titans realize how important their friendship really is. They spontaneously start to participate in the Tamaranean holiday, much to Starfire's joy, and Robin begins to express an earnest interest in his future identity...
From Warp's perspective at least, Starfire committed a time paradox.
Starfire says "Oh, it's never too late" at the end, the only time she uses a contraction noun.
It is unknown why Raven was shown with a white cloak in this episode, but it is likely due to the fact that her insanity resulted in none of her emotions being prominent, therefore representing full and complete balance; her insanity also causing her to lose control of said emotions.
The future world is set 20 years into the future, but hasn't been destroyed by Raven as she did in Season 4 (which was not 20 years ahead of present time). A possible explanation is that Raven's insanity rendered her mind inaccessible by Trigon, therefore his "gem/portal" became useless.
The two teenagers that were harassing future Beast Boy resemble members of the Mutant Gang from the graphic novel The Dark Knight Returns, which was another story that is set in the future.
This episode is very similar to an episode of the 2003 series of Teenage Mutant Ninja Turtles called Same As It Never Was, where Donatello is sent into a possible future in another dimension thirty years from his time, where the Shredder rules the world, Raphael is missing an eye, Leonardo is possibly blind, Michelangelo is missing his arm, Master Splinter and Casey Jones are dead and his brothers are no longer a team. Donatello's brothers all die in the end of that episode, and Donatello is sent back to his dimension.