In all cultures, nursery rhymes and the musicality of voices give rhythm to the lives of babies and children. They have a containing function and form a “wrapping of sound” (Anzieu, 1976). Building on this postulate, we have used nursery rhymes as a form of mediation within a therapeutic group. The objective of this qualitative study is to examine the therapeutic aspect of groups and to explore a form of mediation that is little theorized. The group is made up of five-year-old children, each of whom was faced with potentially traumatic situations in early childhood and each of whom have significant difficulties both with connecting to other children and with allowing themselves to relate to others. The observation of the gestures and movements thus brought about in the group leads us to draw a parallel between this instance of practical implementation and already elaborated theories concerning the group psychic apparatus (Kaës, 1976) and therapeutic groups of children. In addition, we examine the place of the therapist and of mediation in the therapeutic process.