Four girls. One summer. And a pact to do the impossible.   Skyler, Ellie, Scarlett, and Amelia Grace are forced to spend the summer at the lake house where their moms became best friends. One can’t wait. One would rather gnaw off her own arm than hang out with a bunch of strangers just so their moms can drink too much wine and sing Journey at two o'clock in the morning. Two are sisters. Three are currently feuding with their mothers. One is hiding how bad her joint pain has g