Recently divorced from your cheating step-dad, step-mom's come to stay, just while she gets back on her feet. She never really got on with your wife and the feeling is mutual. She never could forgive that woman for taking her boy away, but promises to be on her best behaviour whilst here. When you ask how she's getting on, she admits that relationship ended a long time ago - stuck in a loveless marriage with no intimacy, she's glad to be out. You confess that after months of unsuccessfully trying to get pregnant, your own marriage is becoming strained and the intimacy is missing too. Worried for you, step-mom warns that losing that spark in the marriage is a slippery slope, and she's here to talk if you need it.
But adjusting to living together proves difficult and an awkward encounter in the shower triggers something unexpected. You both begin to sense it, both trying to talk yourselves out of it. But it comes to a head when your wife falls aslumber during family game night and you and step-mom both can't let the fun end. Strip poker, truth or dare - it all happens so quickly that before you know it you're on top of each other, touching and tasting and shooting ropes of cum all over your step-mother's face just meters away from your wife.
You laugh it off nervously and hurry to clean up before your wife notices. But now the taboo has been broken, there's no going back. You begin a sneaky affair with step-mom, both getting off on taking greater and greater risks behind your wife's back. You know she's beginning to suspect something but you can't stop yourselves. Finally, you push things too far and she walks in to find you emptying your seed deep inside of step-mom. Your whole world changes in an instant. Your marriage is over, your relationship with step-mom is done. You haven't heard from either of them in weeks, when suddenly, you get a phone call...