Someone has broken into Remy's house and stolen his notebook, so he gathers his Critter Crew to try to find it. The notebook where his grandfather kept sketches is all he has left of his family, who were scattered after their home was torn down. Buttercup, a cat new to the neighborhood, tries to help, but is rather crafty and mean and gets Remy and his crew into some trouble. The group ends up in the sewers, where they are almost eaten by an evil alligator, but Buttercup proves he is on their side and saves the day. The investigation continues, with Remy visiting a local cafe and getting some clues about an animal in a hoodie who was seen skulking around his house. When Remy finally locates the mysterious creature, secrets about their shared past are revealed.