As Miss Beelzebub Likes It. - Season 1 Episode 9 They Pass Each Other by Sometimes. / I Had a Dream.
Overview: Mullin jokes that he might put in a transfer request and Beelzebub takes it pretty hard. Mullin gets worried that he might have upset her, so he goes to Astaroth for advice. Meanwhile, Belphegor can't help but run away when she sees Azazel. Belphegor wishes she could tell Azazel how she feels, but just can't work up the courage, and that's when she runs into him in the library...