The former price boxer Leo sits his days in the old people's home bluntly and silently. However, he would rather be with a friend in France. Leo's calm ends abruptly when 16-year-old Jojo appears. The teenager must do his probation for mopedieft in the old people's home. He just wanted to impress the leader of his clique, who mocked him as a thank you. As in the ring, Leo and Jojo are like opponents.

But Leo soon breaks his silence, and the likeable grandmother Jojo is very little. Because the old boxer has some good tips, just as the young person can discover his fighter heart to get his life in order. A crazy friendship begins that completely changes the life of the initial opponents.

In Lutz Hübner's fast -paced piece "The heart of a boxer", two outsiders fight back into life. It is a story about friendship and about what can learn old and young from each other. Lutz Hübner has been one of the most played contemporary dramatists in Germany since the late 1990s. He writes most of his pieces together with his wife Sarah Nemitz.