Rosario to Vampire is a schoolboy harem comedic anime. Tsukune Aono somehow ends up in a prestigious and remote private school that turns out to be a secret school for monsters trying to integrate with humans. Fortunately for him the rule is everyone must remain in human form. Unfortunately for him he often gets into fights where his opponents turn into their monster forms.

Before he even gets to the academy Tsukune meets Moka Kashiya and immediately falls in love. And she returns it and soon discovers he's a human but she's ok with it. Moka turns out to be a powerful vampire (strangely when she turns into monster form it's like an older Moka with a different personality unlike every other monster whose monster form is still the same personality as their human form). In any case almost every episode ends in a battle where vampire Moka beats the monster bad guy.

This being a harem series the first few episodes introduce different bad guys (or really bad girls) who end up joining the two's social circle. Kurumu Kurono, a succubus trying to charm all the school boys; Yukari Sendou, a young witch who falls for Mako; Mizore Shirayuki, a snow woman who thinks Tsukune is her only kindred soul.

As the series goes on the group joins the newspaper club and in the final episodes comes up against the machinations of the Protection Committee, a secret cabal of students that almost runs the school by bullying and extorting all the school clubs. It is because of Tsukune's compassion, decency, and human values that the group prevails and the school sees Tsukune as the real hero, a monster that never breaks human form...

Although a bit too fan service-y (lots of cleavage and panty shots) it's an ok series. It takes a while for the series plot to develop and the first half is pretty repetitive. But it gets better and the ending works out nicely.