One morning, out for one of its usual walks, a field mouse discovers something rather unusual: a mysterious blue object sitting at the foot of a big rock. As a group of animals gather to carefully inspect the object, they realize that a robin's egg has rolled down from its nest all the way at the top. Wondering who will roll it back up, the field mouse quickly volunteers, only to be met with laughter and mockery from its fellow animals. The field mouse, spurred on by a determination to prove them wrong, musters all of its strength to take on the task -- but will it succeed?