The Niji's Promise
Second Ship and First Ship of Circus are off to save Karoku. They manage to take over the security system and take over the mansion, but they can't find Karoku!Karoku is shown with another person talking about Nai coming. Nai remembers his days as an animal with Karoku and reaches for the sky, where the forest opens a rainbow gate, assumedly to Karoku.
Aired 20/06/2013EP 12 - The Niji's Promise
2013
Karneval (TV)
Armed with only an abandoned bracelet as a clue, Nai searches for a missing loved one. After a run-in with a pick-pocket named Gareki, the two find themselves snagged in a government set-up that leaves them both wanted criminals. Desperate and on the run, Nai and Gareki turn to the country’s most powerful defense organization—“Circus”—for help.
(Source: Crunchyroll)