Arriving at school, Rosalie discovers that the tree in the school yard was struck by lightning! With her friends Théo and Félix, they were very attached to it, loved playing under its arms, in its leaves. But the next day, the tree was cut down... The adults want to make a picnic table out of its stump. To this news, Théo becomes almost mute, while Félix already plays other games. Rosalie needs a bit more time to accept this change. Then, a new idea...