Grand Theft Auto IV has two dramatically different endings: Deal and Revenge. This page lists the events of both endings.
The Lead Up
One Last Thing (No reward)
Jimmy Pegorino calls Niko and asks him to meet him at the Honkers Gentlemen's Club in Alderney. There, Pegorino asks him to conduct a heroin deal with Dimitri Rascalov, which Pegorino will pay Niko $250,000 for. Niko, however, is reluctant to do so because of the animosity between him and Rascalov. After Pegorino leaves, Niko phones his cousin Roman and friend Kate McReary. Roman encourages Niko to conduct the deal, claiming Rascalov has changed and that Roman can use the money to take himself and Niko on holiday. Kate, however, urges Niko not to do the deal, claiming that he should not sacrifice his principles for money or take his chances with Rascalov.
After this phone call is made, a green dollar sign icon appears on the map for the Deal option, and a red dagger icon appears on the map for the Revenge option. To make their choice, the player simply enters that icon to start the first mission of the chosen ending route.
If the Price is Right ($250,000)
If the player chooses Deal, Niko meets Phil Bell in a townhouse in Tudor. They drive to Port Tudor where the deal is to take place. It turns out however that Rascalov is after his revenge. He killed the people who Niko was supposed to make the deal with. Niko and Phil, in the third-parties compound, decide to steal the money, with Niko planning to kill Rascalov later.
They enter the warehouse from the roof, and find themselves in a gunfight. After killing most of the men, they make their way to the room with the money, only to see someone else escaping with it. They chase the thief down, killing him and collect their money. Niko takes Phil back to Tudor and both of them declare themselves "out" of the crime business.
Mr and Mrs Bellic (No Reward)
The day before Roman's wedding to Mallorie Bardas, Niko phones Kate and informs her that he chose to do the deal with Rascalov. Kate becomes angry at Niko for sacrificing his principles and refuses to come to the wedding.
The next day, Niko goes to the wedding alone and witnesses Roman and Mallorie get married. During the celebrations outside the church, a man walks up behind Niko and points a gun at him, claiming it is "a gift from Dimitri Rascalov". Niko wrestles with the man, and after a stray shot is fired, succeeds in forcing the pistol back and shooting the man in the head. The stray shot, however, had hit Roman in the chest and killed him. Enraged at his cousin's death, Niko shoots the man's body until the gun runs out of ammunition and then starts kicking it. Niko's friend Jacob restrains him and tells him to go home, promising Niko that he will find Rascalov.
A Revenger's Tragedy (No Reward)
The following morning, Niko receives a phone call from Jacob who explains that he has found some of Rascalov's men. Niko meets Jacob in Alderney and they chase the men to an abandoned casino. Despite Jacob wanting to aid Niko in the fight, Niko insists he 'must do this alone'. Niko tells Jacob that if he really wants to help, he should find a way to help him escape. After fighting through Rascalov's men, Niko fights his way into the casino.
Inside the casino, Niko witnesses Rascalov execute Jimmy Pegorino, with Rascalov claiming he wants to keep the money for himself.
Rascalov spots Niko and flees to the casino's roof. On the roof, Rascalov boards a helicopter. Niko grabs hold of the helicopter but one of Rascalov's men stomps on one of Niko's hands, causing him to fall off.
Niko lands in the ocean and jumps into a nearby boat and resumes chase. In the middle of the chase, Jacob arrives in a helicopter and tells Niko to get in. Niko stands up on the boat and pulls himself up into Jacob's Annihilator, where he takes the wheel.
After a brief chase, both helicopters crash on Happiness Island, where Niko chases and kills Rascalov for his betrayal and for orchastrating Roman's death. Jacob arrives and congratulates Niko for "winning", before both men walk away from Rascalov's body and leave the Island.
Following this, Niko receives a call from Mallorie, who informs Niko that she is pregnant with Roman's child. Niko promises Mallorie that her child "will never have to worry about anything". Niko later receives a call from Kate, who laments Roman's death, and states that she'll be there for Niko if he ever needs her.
A Dish Served Cold (No Reward)
If the player chooses Revenge, Niko betrays Pegorino and confronts Rascalov alone on the Platypus ship docked in East Hook, which the heroin is being unloaded from. After fighting his way onto the ship, Niko confronts Rascalov in the ship's cargo hold. After a brief gunfight in which Niko kills Rascalov's guards, Niko confronts a severely-injured Rascalov. Rascalov claims that killing him would be a "big mistake", but Niko ignores this and executes Rascalov.
Niko disembarks from the ship and phones Roman when he is back on the docks, claiming "it ended where it began" (the Platypus was the ship that brought Niko to Liberty City). Roman expresses his disappointment at not getting the money, but appreciates that Rascalov will not bother them any more. Phil Bell also phones Niko, telling him that he made the right decision and that Phil didn't trust Rascalov either. However, Jimmy Pegorino and the Pegorinos are "falling apart" due to the deal not going through, and because of this, Phil and Niko cannot speak to each other anymore. Both men part on good terms.
Mr and Mrs Bellic (No Reward)
On the morning of Roman's wedding to Mallorie Bardas, Niko phones Kate and tells her that he "cut his ties" with Rascalov. Kate congratulates Niko for this and tells him that she will be coming to the wedding. Niko picks Kate up from her mother's house and they drive to the church. During the journey, Niko expresses his desire to leave his criminal lifestyle behind, and that he also wants to get to know Kate better.
Niko and Kate arrive at the church and witness Roman and Mallorie get married. During the celebrations outside, a black car drives past and an enraged Jimmy Pegorino fires at the crowd whilst shouting "You fucking double-crossing immigrant shit!" at Niko. The car speeds off and during the chaos, Niko reveals that Kate has been killed. Roman tells Niko not to blame himself, but Niko lashes out and claims he is responsible. Jacob Hughes and Roman calm Niko down, promising they will find Pegorino. Niko flees the scene and off-screen returns to the South Bohan Safehouse.
Out of Commission ($250,000)
The following day, Niko receives a phone call from Jacob and Roman, who explain that they have found some of Pegorino's men. After meeting the duo, they chase the men through Alderney to an abandoned casino. Niko tells Jacob to lead Roman to safety, before fighting his way through the casino and chasing Pegorino out of the building.
After a brief chase, Niko disables Pegorino's speedboat with the Annihilator's miniguns, while an RPG shot damages the helicopter's engines and forces it to land, both parties now ending up on Happiness Island. Niko chases and kills Pegorino for killing Kate. Roman and Jacob tell Niko that it is "over" and Niko has "won". Roman, Jacob and Niko walk away from Pegorino's body and leave the Island.
A few days later, Niko receives a phone call from Kate's brother Patrick, who claims that Kate "didn't deserve to die" and that the McReary men were the "sinners". Niko also receives a call from Roman, who informs him that Mallorie is pregnant and that if the baby is a girl, they will name her in Kate's memory.