Yabun ni Kyuuketsu Shitsureishimasu.

A 40-year-old office worker named Minoru Sayo leads a normal but uneventful life until he suddenly becomes a vampire. Struggling with his new condition, he avoids drinking human blood and tries using cat blood instead. One night, while searching for a cat, he encounters his coworker Yamadera. After sharing a few drinks, Yamadera falls asleep at a train station, leaving his neck exposed. Sayo, frustrated and hungry, bites him, leading to unexpected consequences. The story explores Sayo's attempts to regain his humanity and the hidden nature behind Yamadera's friendly exterior.