Smoking Behind the Supermarket with You, Volume 1 (by Jinushi)

Sasaki, an overworked salaryman, finds a release of his daily tensions in the customer service of Yamada, a winsome, cheery supermarket cashier. One day he finds himself working late, and, finding Yamada already done with work for the day, goes for a smoke, he finds a mysterious woman, "Tayama", who invites him to the smoking area behind the store.