歓迎会で終電を逃した僕に「先輩うちに泊まっていきます？」と肉食系の新卒女子が小悪魔な甘い囁き。誘惑に負けて何度もSEXした

The protagonist attends a party for new employees and misses the last train home. Eimi, a rookie employee, offers him to stay at her house. Things get awkward fast, as he has a girlfriend waiting for him, but she is proactively hitting on him.