Hotta Sumire

A woman who is working at a fitness club in her neighborhood. She divorced with her cheating husband right after giving birth to her son Takao, who is currently 3 years old. She's raising him on her own. Has a fresh and boyish look, but is earnest and straightforward. Is overflowing with maternal instincts, and thus she is good at looking after people.

Spoiler

It is implied that she actually sees her son in a sexual light after enjoying sex with a man while in front of her sleeping son.