The Inheritance Games by Jennifer Lynn Barnes

A BILLION-DOLLAR FORTUNE TO DIE FOR. Avery has a plan: keep her head down, work hard for a better future. Then an eccentric billionaire dies, leaving her almost his entire fortune.

And no one, least of all Avery, knows why. A DEADLY GAME. Now she must move into the mansion she's inherited.

It's filled with secrets and codes, and the old man's surviving relatives -a family hell-bent on discovering why Avery got 'their' money. WINNER TAKES ALL. Soon she is caught in a deadly game that everyone in this strange family is playing.

But just how far will they go to keep their fortune?