Following the events of THE CASE OF THE CHICANE MUTINY, Stanley's friend and AUNT's best pilot, Tyler, gets a chance to be a field agent. Tyler dives into his training enthusiastically, learning spycraft from Stanley, Marco, Frank, and Cue in ways he doesn't expect. Tyler exceeds expectations and even teaches Stanley a thing or two.

During his training, however, Tyler begins to feel different, and learns it's his time to transition from a caterpillar.Worried he has to resign from AUNT, Director Leo and Stanley assure Tyler he will always have a place at AUNT and on Stanley's team. Stanley and his team help Tyler to make his transition go as smoothly as possible.

Tyler emerges from his cocoon a brand new insectoid: he's now a butterfly! After learning to fly, Tyler decides he should visit his family, whom he hasn't seen since he joined AUNT. Nervous, he asks Stanley to join him, and Stanley agrees. The visit goes poorly, thanks to Tyler's nasty brothers constant harassment.

After resuming his training, Tyler has lunch with his mother, hoping the reunion will go better if it's just the two of them.It goes worse! Tyler is kidnapped during their lunch!

Tyler's mother calls Stanley in a panic, and the Bear from AUNT and his team go to work! They learn Tyler was kidnapped by a group that wants to prevent insects from transitioning, and tries to "fix" those that do - can Stanley and AUNT stop the group in time to save Tyler?

THE BEAR FROM AUNT is a series of illustrated chapter books for mid-grade readers featuring super-bear-spy Stanley and his fellow agents saving the world. This is the fourth in the series, which is designed to be read in any order, available from Crass Fed Kids and Deans Family Productions.