Sasami returns from a trip to Tenchi's aunt's house. Sasami appears a little shy and hides behind Ayeka when Tenchi comes out. We find out that Tenchi's aunt is now a grandmother and Tenchi invites her to come back again and to bring the baby next time.

Later the doorbell rings and Tenchi answers to find his aunt. She thrusts the baby into his arms stating that his mother is sick and "asks" that Tenchi and the girls take care of him until she is feeling better. Before Tenchi can say anything to the contrary, his aunt is already down the path.

Tenchi and the girls (mostly the girls) are having a rough time keeping up with clean diapers and general baby-taking-care-of things. During the night, the baby awakes while the girls are asleep and wonders into Washu's lab. Washu takes the baby and finds the girls sleeping. She proceeds to concoct her own brand of formula for the baby.

In the morning, when Tenchi awakes, he finds that the girls are still sleeping and the baby is gone. He hears noises from the kitchen and finds Washu with the baby in there cooking breakfast. Washu pretends to be upset and wanders off to her lab as the girls come into the kitchen to take over.

Washu cannot work as she keeps thinking of the baby. She returns from her lab to find the girls once again asleep and the baby making a mess. She takes him to the onsen where they both take a bath. Here she has some memories of another baby and a man. She's in for a surprise as her thoughts clear and the baby does a "number two" in the bath.

Washu takes over the motherly duties with the baby as the girls continue to do the cleaning up. Ayeka and Ryoko appear to resent her when they see her and Tenchi feeding the baby.

Later, that night, Tenchi talks with Washu who shows a good understanding of how babies are. Tenchi tells her of his mother and how he lost her when he was very little. He wonders if the way that Washu is with the baby is how he and his mother were. Washu tells him that that is exactly how they were.

Washu is making breakfast the next morning when the baby's father and grandmother come for him. As they leave, Washu tells Tenchi about how she was once married and that the father was from a prestigious family. They had a baby and the father's family took him away from her. Because of this and the way that the adults had put social status above all else, she decided that she would live in the body of a child. Tenchi is touched by her story and as he turns to hug her he notices that she has turned into an adult. She tells him she wouldn't mind having his child. Ryoko, watching with Ayeka, is jealous of this and knocks Washu away from Tenchi. Ayeka then does the same to Ryoko and a small tussle over Tenchi occurs.

The scene shifts to the upper floor of Tenchi's house where we see Sasami with Ryo-Ohki looking down at the fight. She has a sad look on her face and we are left with the feeling that something more is going on behind those eyes.