Appears to be a companion card game to Freche Mädchen - Liebe, Jungs & Mädchenträume, also by Kosmos for the same gender and age group, based on the Sassy Girls, Sassy Books series. http://www.frechemaedchen.de/
The “Song for Tom” is set in the world of showbiz and music competitions. The players all have a crush on bitter-sweet Tom. Each player tries to form "girl groups" to win the contest first with a foursome, then a trio, and finally as a duo of musician cards. The first to complete a group receives a lucky stone as a reward. It takes three stones to win but heart-breaker Tom can appear at anytime to change the line-up.