Love Hina: Totsuzen no Engage Happening

After failing the Tokyo University entrance exam, Keitaro Urashima is nowhere near achieving his goal of entering Todai and meeting his fabled 'promise girl.' Or is he? When Granny Hinata spots his latest poor scores, she decides to send a real Todai student, Mizuho Fujisawa, to help Keitaro, Naru, and Mutsumi pass. Mizuho bears an uncanny resemblance to the girl Keitaro made a promise to years ago. So confident in her teaching, she makes a wager: If Keitaro can't pass under her tutelage, he'll have to marry her. Just who in the world is she?