A Very Special Occasion: Men Wedding!

Nariyuki, a man who's always swayed by emotion, met a man at his older sister's wedding who is...dressed in a wedding dress?! As he's getting over the shock of seeing a muscular boy in a wedding dress, the man says, "The person I was going to marry is not here and might have got in an accident. Help me find him!" Now Nariyuki has to go around everywhere to find him?! How did he get involved into such a mess...!?