Rex and Mimi find naked Cassie and Lucas in bed together, and it looks like they have committed incest! Lucas is furious at the interruption, and he and Rex almost come to blows. Rex finally gets through to Cassie, who asks Lucas to leave them alone. Rex breaks the devastating news to Cassie...Kate Roberts is their biological mother...and Cassie just had sex with her half-brother! Cassie reels from the bombshell. Finally, she tells Rex that she did not go all the way with Lucas. Rex and Mimi are very relieved, but we see Cassie is traumatized by this news. Rex warns Cassie... don't tell anyone, even Lucas, the truth. Rex wants them to stay DiMeras. Rex worries what Cassie will do as she races out.
Sami is devastated that Lucas stood her up. She writes him a nasty note. Lucas arrives home, and Sami attacks him. He didn't know about their supposed date - Will must have forgotten to give him the note -- but Sami calls him a liar. He was out with Cassie tonight. Just when Lucas tells her whom he spends his time with is his business, Cassie interrupts them. She tells Lucas it's over. She never wants him to touch her again - he makes her sick! Lucas is totally thrown, but Sami is privately pleased.
Roman and Kate come across Philip at the Brady Pub. They discuss their various children. Kate hates to think that Lucas is involved with Cassie DiMera. But at least he's not with Sami. Roman is offended. They finally agree to not speak of their children at all.
Victor and Brady catch Nicole searching for bullets. Nicole has to cover, says she's planning a surprise for Victor, but refuses to give him any hint. Meanwhile, Larry loses patience. He goes out to get bullets for the gun. Nicole panics, but when he returns with the bullets, Larry and Nicole conspire to kill Victor...tonight.
Shawn and Belle meet with Philip at the pub. Philip tries to cover his activities, but Shawn forces the truth out of him. Shawn is furious when he learns that Philip is investigating Tony DiMera. He could have gotten Belle hurt! Belle is annoyed when it becomes clear that the guys don't think she can handle herself. She storms out. Shawn agrees to track Maya for Philip, but he's uneasy, as Philip insists that they leave Belle out of the loop. Later, Brady surprises Belle by offering her his old loft to live in. Belle loves the idea, invites Philip and Shawn over. Shawn apologizes to Belle and they kiss, leaving Philip feeling like the third wheel.