From Grand Theft Wiki
Before the Mission
- Stock up on full health and armour. There is armour half way through the main part of the mission, but get some just for safety. Also get some weaponry. Nothing expensive is needed, so just stock up on any Uzi.
- Go see Elizabeta at her house in Bohan. She is having a party and many people are at her house. She introduces Niko to a biker named Johnny Klebitz. Johnny has a heroin deal that he's nervous about, and Elizabeta wants Niko to go along. She also introduces him to Playboy X, Playboy is also coming along on the deal.
Go to the Exchange Place
- When the cutscene finishes, Niko will drive Playboy to the meet point in Cassidy Street, Schottler in Broker. On the way they have a long discussion (see script).
- When Niko and Playboy arrive at the meet point, Playboy says that the deal is taking place on the third floor of the building, follow him up there.
Escape the Building
- It seems that the buyer has had a bit too much heroin by the way he acts, but it turns out that he's really an undercover police officer. Johnny escapes out the front, but Niko and Playboy go up to the roof and escape out another building.
- When the cutscene finishes, kill all the police on the floor, then go up the stairs, killing all NOOSE officers on the way. Once on the roof, kill all officers up there and go down the other building, killing all officers on the way.
Lose the Wanted Level and Get Playboy Home
- Once outside, grab the nearby car and lose the wanted level.