Set after grand theft auto 4 and the revenge ending,Kate is still alive.After his revenge,Niko and Kate try to move on while an man want's Niko killed.
Roman Bellic and his wife Mallorie was at the car depot.Packie McReary had applied for the job there as his mother wanted him to.Niko and Kate are on an date and come back to find them all.Then,Mallorie collapses and is in labour.Roman phones the ambulance and is rushed into the hospital.Kate then reveals to Packie that she is pregnant as she and Niko were drunk one night.Meanwhile,Niko and Little Jacob are in an ambush by an mafia family.Jacob says that the only way to escape is by stealing an chopper.When they escape,An man shoots at the helicopter which results Jacob getting shot and killed and the copter crashes.
Niko wakes up tied in an basement.The man's named is Scar and he wants Niko to kill himself and Kate will be spared.It turns out that she and Packie were kidnapped and will be shot unless he kills himself.Befour he does,Bruice and Dwayne burst in and save Niko and Packie.Katie is taken hostage and is about to get throwen from the roof.Terrified for her saftey,Kate kicks Scar in the nuts and runs away.
When shootout's happen,Packie discover's Jacob and tells Niko.Niko,Full of Rage,Starts killing the mafia.Meanwhile,Another Mafia group burst in an hospital and where Roman and Mallorie are at.They kidnap Roman and Mallorie is freed.Mallorie leaves her baby in the room with the nurse and phones Kate.Meanwhile,Kate is running away from the mobsters and gets the call.She learns what happened and phones Niko about it.Then,Scar apears and knocks Kate out.
Niko and Packie try to find Roman while Dwayne and Bruice look for Kate.They find Kate tied in an chair and Bruice is shot in the leg and Dwayne is kidnapped.Mallorie,Meanwhile,Learns the mafia is coming for her and she escapes with the baby.When she returns to her new penthouse,She emails her cousion Jimmy who can send an mafia family to save them.
Meanwhile,Packie is lost and Niko saves Roman.Meanwhile,Kate escapes and trys to free Dwayne and Bruice.Then Scar comes in and she escapes.When she runs in the road,She sees the mobsters surrounding her.She phones Niko to tell him what is happening.Niko tells Roman to get Mallorie and he rushes to save Kate.Kate is nearly shot and Niko manages to get her to his safezone.Kate tells them that Dwayne and Bruice are still in there.When Niko is about to go outside,Scar knocks him out and attacks Kate.
Niko wakes up tied in a chair in the house.To his horror,Roman is coming to get his keys as he left it there last week and thinks Niko is safe.Roman comes in but is shot.Niko cries as he is gagged and Kate is taken to the bathroom.Niko sobs more as he hears her getting raped.
Packie finds Dwayne and Bruice and saves them and they manage to escape.As an car chase sends them to Niko's house.They all go inside and find Roman knocked out.They find Niko who is dying from blood loss.Packie is then send into an fight for survival as Scar tries to kill him.Bruice finds Kate inside.Kate then passes out.
Kate wakes up in an hospital.She then sees Packie and her mother.Packie says that Niko is in an coma.While Packie and his mother are talking to an tearful Mallorie,Kate runs up to the roof.Meanwhile,The mafia burst in and start shooting at them.Kate hears the shooting and is about to take her own life.However,Niko saves her as he is out of his coma.Then they see Michelle or Karen.Karen says that she is in love with Scar and she shoots Niko down of the roof.
An saddned Kate jumbs on Karen and she pushes Karen down to the ground.Scar comes in and is about to finish off Kate but Packie shoots him in the head.
It is two years later.Kate's mother is dead and Kate had her baby named Niko.Mallorie and Lauren,Her baby,Walk in.Kate breaks down and says that when Packie went to jail she is stugglieing to cope.Mallorie says that Roman is making an new room for Kate and Niko to move in with them.Kate then agrees and sells the house.
Another year later.Kate then has memories about Niko and confides in Roman that therapy never cured her.Kate then tells Mallorie that Niko was going to marry her and they were going to tell them.Mallorie is saddened and tells her that no love is lost and Kate should move on.However,Mallorie is horrified when she sees her about to shoot herself.Mallorie screams no but is too late.
We then see Packie is out of jail and learns of Kate's death and shoots himself.Mallorie had another baby named Harry.Mallorie and Roman moved to vice city with Susan,Niko and Harry.Bruice finds himself he is an homosexual and Dwayne ends it all by shooting himself.