BOKO-019 My lip (Chu!) friend who I only see on the train

Rion, a lesbian student, falls in love at first sight with Yuri, an office lady whom she occasionally sees on the train. One day, Rion spots Yuri asleep and secretly kisses her. After they kiss a few times, Yuri realizes something is strange... but she doesn't interfere any further, and they enter into a strange relationship where they only kiss when they meet on the train. When they find out who each other are, they sneak off the train and engage in lesbian acts. A lesbian story connected by the lips of two people who love kissing.