The Bathhouse with an Angel
Valkyrie and Kazuto are playing hide and seek. Kazuto finds Valkyrie sleeping in the spaceship. As he wakes her up Valkyrie accidentally turns the switch on in the spaceship making it go haywire.
Aired 04/07/2002EP 1 - The Bathhouse with an Angel
2002
UFO Ultramaiden Valkyrie
UFO Princess Warukyure, aka UFO Princess Walkyrie is about a princess from outer space who accidentally crashes on earth, where Kazuto desperately tries to maintain the public bath of his grandfather. Due to circumstances, Kazuto receives part of princess Walkyrie's soul which forces her to stay there with him. But that's not the only problem ... because her soul lost strength, the princess transforms both mentally and physically into a little kid!
(Source: AniDB)