Playable

A veteran of the Balkan wars who arrives in Liberty City on his cousin's promise of a mansion and finds a cab office and a debt. He stays because the man who sold out his unit is somewhere in the city.
All 90 missions · 2 as giver
GTA IV
82of 90
Mission 82 of 90Story mission
Kim Young-Guk — the man Niko escorted down the river for Derrick McReary — is now a target, and he is eating in a restaurant. The mission is an interior hunt: fight up through the building, get the manager to say where Kim is, and catch him before he reaches the back door.
The kitchen chase at the end of it is one of the game's better small set-pieces.
It starts at the door with the receptionist and continues through Kim's men on the ground floor. An SMG and a combat shotgun between them cover the range this mission works at.
He is upstairs, and pointing a weapon at him is what gets Kim's location out of him. There is body armour in his office worth taking. Killing him first does not fail the mission — the game sends Niko to the kitchen anyway.
More of them come through the doors as Niko crosses it, and Kim goes down the fire escape.
He leaves in a PMP 600 and there is an NRG 900 nearby to follow on. An RPG will also reach him before he gets into the car at all, which ends the mission on the spot.
Who this mission brings together, and the ground it covers.
Playable

A veteran of the Balkan wars who arrives in Liberty City on his cousin's promise of a mansion and finds a cab office and a debt. He stays because the man who sold out his unit is somewhere in the city.
All 90 missions · 2 as giver
Gives the job

The dying head of the Gambetti family, running the city's oldest organisation from a hospital bed and still able to make one useful introduction.
3 of 90 missions · 3 as giver