Afterwalkers

Grave robbery, murder and fear... For hundreds of years the people
of Alderston have guarded a terrible secret. When Jamie's family
receive a summons to do a mysterious job, they move into a house
that looks over the graveyard. Soon Jamie witnesses a series of
strange visions and terrible attacks. He begins to suspect that
the great iron cages placed on top of the graves are not there to
keep robbers out, but to keep the dead in. A curse rests on the
town. The undead are in charge, and somehow Jamie is the only hope.