Tatoeba Haha ga

Masaki is a college student who shares a home with his single mother, Yoshiharu. Despite their familial bond, their daily dynamic resembles that of detached roommates rather than a traditional parent and child. This distant arrangement allows both to maintain separate lives, but Masaki soon begins to notice unsettling details that challenge the quiet routine they have established. Late one night, when Yoshiharu returns home, Masaki spots strange marks on her neck. These physical signs lead him to suspect that she might not be spending her evenings working as she consistently claims. When confronted, she firmly denies being romantically involved with anyone, yet the unexplained marks only continue to multiply over time, deepening his suspicion and unease. The situation grows increasingly complicated following an unexpected run-in with the boyfriend of a woman Masaki has been casually sleeping with. Shaken by this encounter, he later spots his mother in the company of a man whose face strikes him as disturbingly familiar. Caught between his own tangled personal life and the growing mystery surrounding his mother's secret activities, Masaki finds himself drawn into a web of hidden truths that neither of them anticipated.