While searching for Mrs. Twombly's missing glasses, Blythe comes across Shivers, a fast-talking squirrel with a hoarding problem. When Blythe and the pets realize Shivers is at fault for items missing from Littlest Pet Shop, they try to help him face his issue.
After losing a ball while playing catching, Minka and Penny Ling try to retrieve it when it rolls into a natural history museum. Blythe tries to retrieve the two without losing all the other pets, but finds out that the museum disallows animals. She conceals the rest in her bags and backpack, but as she spots the two that were missing, Zoe flees from her bag upon inspection from the museum's security guard. Now with three of the pets missing, Blythe must manage to find them all, eventually losing the rest in the process: Sunil and Vinnie in the taxidermy section, and Russell in a supply closet.
The pets are driven to madness trying to identify a hum resonating from inside the shop, while Blythe runs for class president against the Biskits.
Blythe tries to resolve her feelings for Josh Sharp; meanwhile, Russell becomes the subject of a love spell while trying to stop a secret pet "cupid".
Stolen merchandise from Largest Ever Pet Shop lands in Blythe's dumbwaiter. She asks Pepper and Vinnie to investigate. and their search for the culprit leads to the discovery of an elaborate tube system dug out by two hamsters, Dodger and Twist.