Tyrannosaurus Rex enthusiast Sal transforms herself into an uncontrollable T. Rex, partly because her brother said it would be impossible, but soon discovers the downsides of always being fierce.

When a fight breaks out among the members of the Baby-sitters Club, timid Mary Anne finds herself becoming more assertive as a babysitter and in her relationships with her father and friends.

Aria loves her soft and bouncy hair, but must go to extremes to avoid people who touch it without permission until, finally, she speaks up. Includes author's note.