Hanna is always in trouble with her parents for using the phone! Now there's going to be an end to it all. She's going to get a mobile phone for her birthday. It's hardly surprising that her friends Kati and Mila are a little bit jealous. Until one day Hanna's mobile just doesn't stop ringing. Love messages keep arriving at almost every time of the day or night. Some of them are sung, others are little poems, and sometimes they are text messages. Hanna can get no peace. The three girls spend their time puzzling about who the secret admirer could be. Mila reckons it's Markus, Kati thinks it is Tobias. But Hanna has got another idea ...