His Partner, the Thoroughbred Omega

Leo Asaka, an alpha male and a second-generation actor, hates it when people say he's just like his actor father. Leo is working hard to make it big on his own when he receives an offer to star in a film to be shot by a world-famous director. He then learns who his co-star is: Eito Yanagi, another alpha male and a second-generation actor who's known for living a scandalous life. The two of them get locked in a hotel room so they can get to know each other, where Leo glimpses a secret about Eito that may change the course of their destiny.
(Source: Renta!)

Note: Contains an extra chapter.