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.
At the Kiriakis Stables, Larry and Nicole went over plans to kill Victor. Inside the Mansion, Brady was irritating Victor with questions and observations about what appeared to be a bad marriage. Nicole interrupted to invite Victor to meet her for a "surprise" by the pool.
At the Echelon Club, Bo and Hope were undercover trying to recover their stolen SUV and the thief. Meanwhile, Cassie was trying to get a job there as a hostess. Upon being hired, she was delighted at the thought of being popular - not quite realizing what she was getting involved in.
At Sami's apartment, Sami's statement that Cassie had dumped Lucas angered him so that he threw her writing board aside. Reminding her of past deeds to hurt him, Lucas reduced her to tears wishing she wasn't Will's mother. But when her throat wounds began to bleed through the bandages, Lucas was reminded of the accident. Retaining his composure, he helped Sami, and left her with an "I'm sorry" on her board.
At the Kiriakis Mansion, Nicole watched from her window waiting for Victor to arrive at the pool when she heard him upstairs. Curious about the surprise for Victor, Brady had strolled outside. Mistaken for his grandfather in the dark, Brady was shot by Larry.
On the DiMera Yacht, John tripped a fire alarm to cause a distraction. While Tony left his cabin to investigate the alarm, John searched the cabin finding the laser - and inadvertently, the bomb inside the fruit basket. Tony's anger at finding John in his cabin, cost them valuable time as John convinced him there was bomb on board. Seconds after they left the cabin, the bomb exploded.
Tony and John, unconscious, are trapped in a submerged section of Tony's yacht. Tony saves John's life. They take turns diving down, looking for a way out. Later, when Tony has been gone too long, John dives down and saves Tony, who had been trapped below. They realize there's no way out... they're trapped and slowly running out of air. They realize their old animosities won't help in this situation.
Meanwhile, Shawn visits Maya in her office (on a spying expedition for Philip). He overhears her getting the news that the bomb was delivered to the boat, but Maya covers. Maya plays it very close to the vest, reveals nothing, and continues to flirt big time with Shawn. Shawn leaves, frustrated not to have gotten any information. Maya's pleased when she gets a call telling her the bomb's gone off and Tony's yacht is sinking.
At Echelon, Hope is concerned that Tommy found Bo's earpiece in the parking lot and Jesse, the bail jumper, is in the club. We see Bo lying in the back seat of the SUV. Hope and Tommy decide to go with the original plan. Tommy pretends he wants to buy the "hot" car and Jesse takes him outside. Hope follows, but is detained by a curious Lucas, who wants to know what she's doing there? In the car, Bo appears, seeming to have the drop on Jesse. But Jesse recognized Hope, knew Bo would show up, and has a gun on Tommy, threatening his life. He makes Bo get on the floor and has Tommy drive them to an alley, where he plans to kill them both. Hope, having gotten away from Lucas, sees the car drive off and follows. Just as Jesse is about to shoot Bo, Hope honks the horn, providing a distraction and enabling Bo to overpower Jesse, save Tommy's life... and get their car back!
While Larry realizes he shot Brady instead of Victor, Nicole frantically drags Brady out of the pool and performs mouth-to-mouth. Victor overhears her say that it was a stupid mistake, but she covers. Once Brady is breathing again, Brady insists he wasn't shot. When he heard the gun go off, he turned, fell into the pool and hit his head. Nicole is very relieved. Victor, armed, heads into the bushes where Larry was, but he has already taken off. Abe and paramedics arrive. Abe first thinks the hit was meant for Victor, but Brady thinks some rough musicians he fired from the Blue Note could have targeted him. Abe will investigate. Victor is solicitous of Brady, warns him to be careful. Brady will, but speculates: what if Victor really was the target of the hit? Meanwhile, Nicole gets a call from Larry. She wants him to lay low. Larry refuses. He wants to go ahead and murder Victor tomorrow!
John and Tony cling to life trapped in the wreckage of Tony's sunken yacht. They've exhausted every possible means of escape and the air pocket in which they're trapped is rapidly dwindling. John and Tony both find it ironic that, after all they've been through, they're going to die together. Tony reminds John that this bomb was meant for him, and had John not been so hell-bent on bringing his half-brother down and followed him onto the boat, he wouldn't be in this mess. They share a moment as Tony admits he regrets being unable to keep his promise to Cassie and Rex to spend the rest of his life making up for the time they've lost as a family. Ultimately, Tony loses consciousness and slips underneath the water. John also passes out and slips into a watery grave, just as we hear the faint sounds of rescue helicopters approaching, but too late...
Shawn meets up with Belle and Philip at Brady's loft. Stealing a moment away from Belle, Shawn reports to Philip about his meeting with Maya. He mentions that he overheard her talking about a ship, but mistakenly believes that she was talking about the ship where they saw Maya, and Philip concurs. Belle overhears and realizes that the guys are keeping secrets from her again. Busted, they confess, and after a tongue-lashing from Belle, they all agree not to keep any more secrets. Tek arrives and breaks the news about Tony's yacht exploding. Belle is rocked by the news of Tony's presumed death, and her thoughts immediately go to Cassie and Rex who have lost their father. Philip must break the news to Belle that John was also on the ship, and Belle screams in horror.
Rex and Mimi arrive back at his room, Rex consumed with worry about Cassie. Mimi tries to comfort and distract him, but he suddenly jumps up and starts furiously sketching on a piece of paper. Miffed, Mimi gets ready to find something or someone else to entertain her, when instead she comes face-to-face with Cassie. Rex and, to a lesser extend, Mimi try to comfort Cassie, who's still mightily distraught over nearly having sex with Lucas before finding out he was her half-brother. Cassie and Rex vow to never reveal that Roman and Kate are their biological parents and to continue their lives as DiMeras. Later, as Mimi sleeps in his arms, Rex steals out of bed to continue his sketch, determined to further impress Tony and cement his position in the DiMera family. Alone in the corridor, Cassie, feeling that Rex doesn't need her because he has Mimi, breaks down in tears.
Roman and Kate join Abe and Lexie for an evening out at Tuscany, Abe and Lexie's first date since Theo was born. Maggie joins them as they ooh and aah over Abe's baby pictures. In the ladies' room, Kate compliments Lexie on all that she and Abe have overcome to stay together, and on how she handled Sami. Kate wishes she could handle Sami, and explains to Lexie her fear that her and Roman's differences over their kids could be the end of them. Back at the table, Roman is taken aback when Abe wonders if Roman and Kate have considered children. Roman thinks he and Kate are way past that stage in life. Later, Roman jokes with Kate about them having a child together, and her reaction is as adamant as his - never
As Belle received news about John and Tony, Marlena stopped by the apartment to learn as well. Meanwhile, Sami was upset hearing the news from Lucas who consoled her at his apartment.
However, John and Tony were coming to, after being rescued by the Coast Guard. As they were treated by doctors, the two brothers shook hands confirming the truce that began in the water. But when John asked about his trip and who would have planted the bomb, Tony was offended at being "monitored." John agreed to maintain a certain distance - but warned the ISA might not be so lenient.
At the Kiriakis Mansion, Brady was recuperating - still thinking the gunman had targeted him. As Nicole tried to help him, Henderson announced she had a call from "Mr. Ed." Thinking it was a repairman, Brady intercepted the call, to a silent Larry on the other end of the line. Nicole later returned Larry's call saying she wanted to call off the hit. But Larry said he wanted his own revenge over Victor - as well as wanting Nicole.
Recalling Maya's phone conversation about a boat, Shawn connected her to the explosion. Maya's celebration over Tony's demise was cut short when she heard he had survived. As she prepared to leave Salem, Shawn appeared, enticing her to come to his car. Once there he cuffed her, offering to turn her over to Tony or the ISA. Maya chose the ISA.
And at the Rescue Quarters, John returned to the treatment area to find Tony's bed empty except for a note reading: "See you at home, Brother."