On Christmas Day 2005, Sharon is admitted to hospital with suspected food poisoning, but finds out she is pregnant, despite the previous belief that she was infertile. They prepare to leave on New Year's Eve to start a new life in the United States. Sharon does not tell Dennis that Johnny has threatened to kill him if they have not gone by midnight, but she confides in Phil, who then uses Dennis as a weapon against Johnny. Phil tells Dennis about Johnny threatening Sharon and also that Johnny had murdered Andy. Although Dennis realises Phil was manipulating him, he takes the bait anyway and beats Johnny to the brink of death. Johnny begs for help as he thinks he will die, so Dennis tosses him a mobile phone and says if he can reach it, he will live. Johnny is able to reach the phone and instead of calling for medical assistance, he contacts a henchman to murder Dennis as revenge for his beating.
After cleaning his hands of Johnny's blood, Dennis makes his way towards the Albert Square Gardens where the locals are setting up fireworks, to meet Sharon. As they lock eyes, Dennis is stabbed and collapses, dying in Sharon's arms. His last words are "we did it" in reference to their unborn son who was born six months later and named Dennis in honour of his father. It is later revealed that Dennis was killed by Danny Moon (Jake Maskall).