Maeda Takeru is a student who grew up in a single-parent household.
Takeru's mother Kana separated from her husband at an early age and has been raising Takeru alone ever since.
Kana has devoted all her time to Takeru.
Takeru knows this very well. He has reached that age.
Just as Kana has done for him up until now, Takeru has devoted himself to Kana as a way of repaying her kindness.
He keeps socializing with friends to a minimum, and on weekdays when Kana goes to work, he comes straight home, prepares dinner, heats the bath, and waits for Kana to come home.
He is a great son.
It is impossible for Kana, a mother, not to love such a son.
Kana dotes on Takeru.
Takeru, too, perhaps loves his mother more than Kana does.
Perhaps because they are the two of them---there is a relationship between them that is not found in an ordinary mother-son relationship.
"Takeru, I wonder if I can ask you again today..."
And with that, Kana invites her son into bed.
"Of course, mom..."
There's no way he'd turn down an invitation, so Takeru climbs into bed where his mother is waiting.