Arakawa Under the Bridge x Bridge

Synopsis

Under Seki's orders, Shimazaki researches about Nino, but she is threatened by a strange man not to go any further. Meanwhile, Nino reportedly receives a tape from her parents and tells Kou she has to leave the riverbank and return to Venus, asking him to come with her. To Kou's surprise, everyone else starts inviting themselves to come along.

(Source: Wikipedia)