Shishunki Bitter Change

After an accident involving falling from a tree, Yuuta and Yui manage to switch bodies with each other. With many attempts to switch back failed, the two of them are forced to live each-other's lives, with both of them having very different lifestyles and families. Nearly three years pass since the original incident, and the two of them are still stuck in each-other's bodies. How will they cope with their situation as they begin to grow up?