When Life Gives You Lemons, Make Grape Juice

"You see, Jace, you're missing something. My motto just so happens to be, when life gives you lemons, make grape juice and let the world wonder how you did it. Because life never expects that. Plus grape juice is awesome."

Bailey Haart has a great life. With her happy-go-lucky personality, brilliant friends, and caring parents, she would change nothing.
Until she comes home from school one day to find them dead. She is packed off to live with her aunt, who she hasn't seen in 15 years, and she can't help thinking there's something dodgy about her aunt's family.
She has the feeling that she's in grave danger, and only her cousins can help her. But will they be willing to share their secret to save her life?
And why is the mysterious Jacob seem to know everything about the Haart family?