Everything you need to understand or teach Playing for Keeps by Joan Lowery Nixon.
Rosie accompanies her grandmother, Glory, on a Caribbean cruise and becomes involved in a shipboard mystery. Irritated that Glory is trying to be a matchmaker by encouraging a romance with Neil, Rosie falls in love with Cuban exile Ricky Urbino who is a stowaway on the ship. She and Neil cooperate in an attempt to clear Ricky of a murder for which he was falsely accused. Rosie convinces Neil and their new friend...