Brother Bear and Sister Bear usually get along well, sharing chores, toys, and bus seats without complaint. But one gray morning, a small irritation—Sister hogging the bathroom—snowballs into an all-out sibling war. The two stop sharing toys, draw a dividing line down their tree house, and trade barbs at every turn. After Mama Bear blows her whistle and restores order, she points out that they cannot even remember what started the fight. By the next day, the two apologize and scrub the line from the tree house wall—at least until next time.