"I'm not entirely sure, Sam, but I'm starting to think that this might be the end of the world after all."

The end is here. An ancient evil arrives in Rippon, determined to do whatever it takes to get his hands on the Devil's corpse. Abberoth believes the kingdom of Hell is his for the taking, and he won't let anyone stand in his way.

Sam Marker, meanwhile, hasn't even had her first cup of tea this morning.

As the final battle approaches, Sam discovers that she can only count on some of her friends. Abberoth is torturing the entire village, and Sam's only help comes from a ghost, a stone angel and a pile of books. However, another problem quickly emerges. Abberoth might be determined to seize the Devil's corpse, but the Devil himself is far more interested in running the local coffee shop.

Both Abberoth and the Devil are happy to let the world burn, but Sam can't do that. After all, someone far away is depending on her. Someone she abandoned long ago...

The Gravest Girl of All is the third and final book in the Grave Girl trilogy.