Red Line| Momo Hirai X Male Reader

Y/n is the trusted mechanic for TWICE, responsible for maintaining the group's vans and the members' personal vehicles. While everyone knows him as the quiet guy in the garage, they have no idea that once night falls, he becomes one of Seoul's most respected underground street racers, competing in illegal races and high-stakes tournaments on the city's back roads.

Momo discovers his secret after attending an underground race out of curiosity. The adrenaline, the speed, and the mystery surrounding the masked driver immediately draw her in, but it's Y/n himself who keeps her coming back. Instead of trying to pull him away from the racing scene, she chooses to stand beside him.

Using her talent with numbers, Momo becomes Y/n's unofficial accountant, managing his race entry fees, prize money, and expenses while helping him stay focused on the track. As their partnership grows stronger, they must keep his double life hidden from TWICE and the company while navigating the dangers of underground racing and the feelings developing between them.