Everyone but two people forms a circle standing far enough away from each other so that a person can safely run past them on either side. They must also be close enough to reach the hand of the people on either side of them.
One of the people outside of the circle is the cat and the other is the mouse. They will begin on opposite sides of the circle.
When the game starts, the cat tries to catch the mouse. If either the cat or the mouse runs through one of the spaces in the circle, the space gets closed. This is done by holding hands.
The game goes on until all the spaces are closed or one or the other gets trapped inside the circle.