If only she'd said no...
Katherine knew she'd had too many drinks, but they were only going a short distance. And as Eve pointed out, it was late, there was no traffic anyway...
But now, Katherine would give anything to turn back the clock. If anyone ever found out about the accident, it would ruin her life. But no one needs to know because Eve was there too, and she's going to help make it all go away.
Except something's not quite right with Eve, and by the time Katherine realizes that...
It's too late.