I've only watched the first episode so I'm not the best person to do this but...
There is a girl who can see rings around people's necks, when these rings turn black, the person dies. One day she meets two boy, Shito and Chika, who both have black rings around there necks, but neither are dead. It turns out the two boys are zombie hunters who find other people with black rings around their necks and kill them.
The story and characters are pretty cool so far, it also mixed comedy and action decently, but the pacing felt off a bit.
EDIT: Also, I love the opening.
Banned for making me write an overly long post!