In order to complete the mission the player must:
- Meet up with Roman and Jacob, who wait in a car in Alderney.
- Follow Pegorino's goons, they'll lead you to Pegorino.
- Pegorino is inside the old casino. Find him.
- Chase Pegorino.
- Get on the bike.
- Chase Pegorino. Stick to the coastline, do not lose him.
- Accelerate off the jetty to jump.
- Get low and stay close to Pegorino.
- Chase Pegorino.
- Kill Pegorino.
After Roman and Mallorie's wedding in the Revenge ending, Niko, who has been mourning the death of Kate, receives a phone call from Little Jacob telling him he and Roman found some of Jimmy Pegorino's mobsters in a building in Koresh Square in Alderney. Afterwards, the mission automatically starts as Niko goes to the two who are waiting in a Cognoscenti, and they begin to pursue the mobsters to Jimmy Pegorino.
After an extended car chase and dialogue between the three about why Niko is doing this, the two eventually lead them to an abandoned casino in the North of Alderney, with Niko telling Roman and Jacob not to join the fight and they do so. Niko then fights his way into the casino, until he finds Pegorino. Pegorino states that if he would've worked for him things would be better, and Kate's death was Niko's fault. He then runs away and boards a boat on a jetty after letting loose more of his guards which are killed. He then gives chase by using a dirt bike and staying on the shore. After a short while, Roman and Jacob arrive in an Annihilator. Niko then jumps onto it by means of a ramp, and Roman pulls him in the helicopter.
Once aboard, Niko takes over the controls (as Jacob claims that he's bad at flying) and flies over Pegorino's boat with Jacob shooting at it. The boat catches fire but due to a Rocket Launcher shot so does the Annihilator. Jimmy manages to escape from the boat at Happiness Island and run under the Statue of Happiness while Niko safely lands the burning helicopter and goes after Pegorino. Niko then engages in a gun battle with Pegorino, mortally wounding him in the process.
A cutscene then shows Niko confronting Pegorino as he slowly bleeds to death. Niko tells him about knowing people in the Commission and that says they thought he (Pegorino) was "a fat fucking joke", Niko turns his back on Pegorino. As he raises his gun to shoot Niko from behind, Niko quickly turns back and shoots Pegorino in the head, killing him. Roman and Jacob then show up and comfort Niko. Roman explains that now that their enemies are beaten, they can start making money freely and live peacefully. Even though Niko agrees, he is still grieving due to Kate's death. Niko, Roman and Jacob then leave Pegorino's body at the foot of the Statue of Happiness as the camera pans out to show the Liberty City skyline at sunset.
- Jimmy Pegorino - Killed by Niko Bellic for inadvertently killing Kate McReary at Roman Bellic and Mallorie Bardas' wedding and for attempting to kill him.
- Numerous counts of Jimmy Pegorino's men - Killed by Niko Bellic for attempting to prevent him from killing Jimmy Pegorino.
- "You Won" Achievement (Xbox 360/PC)
- "Liberty City Minute" Achievement/Trophy (if the game is finished in less than 30 hours)
- Niko receives a call from Roman, informing him that Mallorie is pregnant and that they will name the baby in Kate's memory if it is a girl.
- Niko receives a call from a tearful Packie, with Packie telling Niko that Kate didn't deserve to die as the McReary men were the "sinners." Packie also tells Niko that he must be there for his mom since he's all she has left.
- Following the credits, Niko says "So this is what the dream feels like, this is the victory we longed for."
Liberty Tree Newspaper
- "Police have found the body of Alderney mob boss, Jimmy Pegorino, on Happiness Island. Mr. Pegorino had captured headlines as the boss of a crime family with designs of power. They were thought to be seeking parity with the Five Families who had been weakened in recent years. After recent legal pressure and escalating bloodbaths in Alderney, crime pundits began to see Pegorino's crew as pretenders, not the real thing. Police responded to reports of both a boat and helicopter crash on Happiness Island. Three suspects were witnessed leaving the scene and are being sought for questioning."
- The car chase scene in the very beginning of this mission is the only occasion when Roman complains about Niko driving fast. Usually he enjoys it and encourages Niko to drive faster, although this could be as he is nervous about the situation.
- The Huntley Sport that Pegorino's goons are in can be blown up with Packie's bomb, after the player calls it. The bomb will go off after a certain amount of time and this will fail the mission.
- Dwayne's backup cannot be called to help with the shootout at the casino.
- One dialogue string that should trigger when Jimmy's men start driving on the other lane against oncoming traffic may be triggered earlier than intended, depending on how far behind is the player, which will lead to things like Roman saying they are taking shots while dodging oncoming traffic when no such thing is happening.
- If the player fails to accelerate off of the jetty on the Sanchez, Pegorino will "escape" and the mission will fail. However, if the player looks at his boat after they fail the mission, they will see someone exiting the boat into the water. They can be followed onto land, and will be holding an AK-47. However, it is a random pedestrian, not Pegorino.
- Even if the player does not have an AK-47 in their inventory, Niko will still hold one in the last cutscene and kill Pegorino with it.
- It is possible to dodge the final rocket that Pegorino fires but the player must be really high in the air and fly to the right near the bottom corner of Alderney. When it shows Jimmy fleeing from the boat the helicopter will be on fire even if the player dodged the last rocket.
- This is one of four final missions in the GTA series in which the main antagonist is not killed (the others being Freedom Flies in GTA Advance and Something Sensible/The Time's Come in GTA V) as in the Revenge ending Dimitri Rascalov was killed in A Dish Served Cold.
- If the player shoots Jimmy's boat with an RPG before entering the casino, the boat will be moved to avoid the explosion of the rocket.
- If the player manages to destroy the boat (by throwing grenades onto it), the mission will fail, with the on-screen message saying that Pegorino has fled.
- This is one of only two missions in GTA IV, (the other being the other final mission, A Revenger's Tragedy) that has a checkpoint the player can restart from if they fail the mission, which is when Niko and Jacob are hiding behind the car. However, in this particular mission, if the player fails a number of times, the mission will restart from the beginning.
- If the player blows up the Sanchez with an RPG, it will not fail the mission then but when the game says to get on the bike, it will say the bike was wrecked and the mission fail there.
- Niko closes the Annihilator's rear doors after boarding it, before it opens again. This is the only time that the rear doors can be closed on the Annihilator.
- The Annihilator is special in which it has a missing tail blade. This also occurs in A Revenger's Tragedy.
- Pegorino will not begin riding away on his Squalo until Niko is within a certain distance and on foot. As such, it is possible, at the right angle and height, to shoot him with a sniper rifle while he's still on the boat. This has no effect other than a blood spray and random dialogue from Niko, as Pegorino can only die on Happiness Island.
- There is a bug in this mission. When trying to climb up in Jacob's Annihilator, the camera changes views instead of showing Niko climbing up in the chopper (found on PC and Xbox). Another option is to hold the move forward key while mashing the climb button.
- There is a typo in the subtitles when Little Jacob says "Pegorino ain't as strong as when he used to run the Alderney family", misspelling the name of the state as "Aldreney".