The Final Gambit by Jennifer Lynn Barnes

To inherit billions, all Avery Kylie Grambs has to do is survive a few more weeks living in Hawthorne House. The paparazzi are dogging her every step. Financial pressures are building. Danger is a fact of life. And the only thing getting Avery through it all is the Hawthorne brothers. Her life is intertwined with theirs. She knows their secrets, and they know her.