From Renta!:

Former office worker Isshin quits his office job to do hard physical labor in the delivery business. As the daily grind wears down his body and soul, his only solace is working with his beloved coworker Haz?. Haz? has it all - good looks and excellent occupational skills. One day, just when Isshin's starting to feel like Haz?'s titillating presence makes his job worthwhile, he makes a mistake during a delivery and Haz? has to pick up after him. On top of that, he gets blackout drunk and makes a total disgrace of himself. When he wakes up, he finds himself with no clothes on, and Haz? by his bedside asking if he remembers what happened last night... That one moment of despair might be the catalyst that brings them together...