Ikemen-kun to Saenai-kun

Kentarou is a dull college student who has never had a girlfriend. Ever since he struck his head, he's been troubled by actions he has no memory of doing. One day, he wakes up in an unfamiliar place in an unfamiliar bed. Next to him is a good-looking young man he's never seen before. Just who is this guy? What's going on? (Source: the manga habit)