In this game the player controls Cornet, a young orphaned girl who can animate lifeless puppets by playing on her trumpet. One day, Cornet meets prince Ferdinand and falls in love with him. She joins a contest, the winner of which will have the privilege to marry the prince. But in the middle of the contest, an evil sorceress bursts in and kidnaps the prince. Now Cornet and her friends must defeat the sorceress and rescue the prince.
Rhapsody: A Musical Adventure is a Japanese-style role-playing game with humorous elements. Cornet's party includes animated puppets and can also contain enemies who may be willing to join it after battles. All the combatants level up automatically after having accumulated a sufficient amount of experience points. Enemy encounters are random, and battles take place on a tactical screen, requiring the player to move characters in a turn-based fashion and attack enemies in range of the characters' weapons.
Characters also learn magic and can equip up to four different accessories instead of the traditional weapons and armor. The world map consists of dots the player can travel to automatically, and only a small portion of it is accessible in the beginning. Story progression is linear. Musical performances are sometimes used as story-advancing cutscenes.