office lady mayu commutes by train every night, working late and taking the last train home. one night, exhausted from work, she falls asleep on the train and is seen by a man across from her. the woman becomes aroused by being seen and masturbates at home. she thinks, if no one is around... and starts masturbating on the empty train. one night, a man sees her and they both start masturbating, forming a strange relationship. the woman beckons the man and has him lick her pussy. the two, excited, have secret sex on the train.