The Covenant (2006)

In the 17th century, five families with supernatural powers make a pact of silence. Eventually one power-hungry family is banished. The descendants of those four remaining families are heirs to tremendous power. Known as the Sons of Ipswich, the boys attend elite Spencer Academy. When a student there is found dead after a party, unraveling secrets threaten to shatter the pact that has protected the boys' families for centuries.