Due to a reason, Tsubaki was separated from her son and came on a solo hot spring trip.
The inn employee Kenta turned out to be Tsubaki's long-lost son.
Even after suddenly reuniting with Tsubaki, Kenta couldn't open his heart.
He resented Tsubaki for not acting like a mother and demanded she offer her body as compensation.
As an act of atonement... Tsubaki decided to have sex with her son.
