Movement at the Surface of a Rain Barrel

Case overview

Nia is closing up the yard at dusk when she notices a faint movement at the surface of the rain barrel behind the shed. The air is still. A leaf drifts near the rim, then the movement appears again. Her nephew Cal says he saw it yesterday too, but only after the warm week. Nia does not know whether the barrel has become a small mystery or just a place where yesterday's weather is still showing. They stand beside the fence, careful not to stir the water. The other containers in the yard and the barrel's lid may help them tell whether this is an isolated change. Nia also wonders when anyone last used the barrel. She wants to know whether the movement appears in other containers before she settles on a routine.