Agent Mittens, a napping cat who fancies himself a detective, is tasked with finding Mrs. Higgins's missing blueberry muffin. Following a crumb trail, he discovers a toy mouse covered in crumbs, leading him to a hidden mouse hole. Inside, he finds Pip, the house mouse, eating the muffin. Agent Mittens alerts Mrs. Higgins, who praises him as a clever detective, solidifying his new, proud reputation.