As a twelve-year-old Welsh immigrant carries a motherless baby along the Mormon Trail in 1856, she comes to love the baby as her own and fear the day the baby's father will reclaim her.
Froggy hoped for a brother to play with so he is disappointed with his new baby sister, Pollywogilina, but only until she is old enough to start learning from her big brother.
The Rugrats decide to make a long road trip less boring by pretending they are on a mission to outer space, but things get scary when they accidentally venture into alien territory.