Osamu Mayuzumi is a cram school teacher. He visits the hospital to donate blood so often that Yuki calls him a “donor nut.” After taking a sip of Mayuzumi’s blood on whim, Yuki finds the taste so good that he craves more. Now, Yuki is trying to get closer to Mayuzumi, and surprisingly, Mayuzumi is also trying to get closer to Yuki. But will their conflicting reasons for getting together derail their relationship?