Der biedere, verheiratete Geschäftsmann Harry Allen (Oscar-Preisträger Chris Cooper) gesteht seinem alten Freund Richard (Pierce Brosnan), dass er sich bis über beide Ohren in die junge Kay (Rachel McAdams) verliebt hat. Da er es nicht übers Herz bringt, seiner Ehefrau Pat (Patricia Clarkson) den Trennungsschock zuzumuten, beschließt der fürsorgliche Harry, sie lieber schonend zu vergiften. Sein mörderischer Plan hat jedoch bald seine teuflischen Tücken, denn Kay, Pat und Richard haben auch ihre kleinen, gemeinen Geheimnisse.
The upright, married businessman Harry Allen (Oscar winner Chris Cooper) confesses to his old friend Richard (Pierce Brosnan) that he is head over heels in love with the young Kay (Rachel McAdams). Since he doesn't have the heart to inflict the separation shock on his wife Pat (Patricia Clarkson), the caring Harry decides to poison her gently. However, his murderous plan soon has its diabolical pitfalls, because Kay, Pat and Richard also have their small, mean secrets.