Lydia, Emily, and Cassie have been best friends through everything, guy problems, family issues and even Secret Assignments. While they all attend a posh private school, each girl has a unique way of expressing herself. Lydia sometimes declares that she is a fish, with the intention of becoming a writer someday. Emily's dream of becoming a lawyer might never gain steam if she can't remember the difference between cinnamon and synonym. And Cassie just wants to stop being too afraid to get up on stage and sing. This year their English teacher has assigned them pen pals from public school Brookfield High to reacquaint them with the Joy of the Envelope. Over the course of the year they each get to know a stranger. Sebastian is an artistic soccer player who sometimes can't control his temper. Charlie is a sweet guy who always seems to be in trouble. And Matthew is either very dangerous or nonexistent. Prank calls, mistaken identities, spy missions, Dates with Girls, with a side of blackmail and revenge make for an interesting year!