After a family tragedy involving arsenic 6 years ago, the remaining 3 still live in the castle isolated from the nearby village. 18 y.o. Merricat shops in the village weekly but it's unpleasant the way many villagers treat her. Her magical spells don't seem to protect her. Her older sister Constance and uncle Julian never leave the property. The sisters' cousin Charles arrives unannounced, not really to meet the family but rather for the money in the big safe. Chaos ensues.