It's War

It's War is a mission in GTA IV DLC The Lost and Damned. It is given by Billy Grey to Johnny Klebitz.

lean up, it isnt Description
This opening cutscene shows Billy Grey talking to a Dave Grossman, a member who is also a lawyer for Goldberg, Ligner and Shyster. Johnny enters and has to talk to Billy, telling Dave to "fuck off" so he can speak privately with Billy. While conversing, Billy receives a text message informing him that members of The Lost were attacked by AOD members.

Walkthrough
You drive to the scene and find a plethora of AOD members in the area. After eliminating all of them, you're ordered back onto your bike and to another location, where a larger concentration of AOD members are holed up. After eliminating the giant amount of enemies at this abandoned site, you're again ordered back to your bike where a cutscene occurs. It appears as if the member you met early in the game, Jason Michaels, has been killed by an Eastern European (Niko Bellic, protagonist of the GTA IV main story, specifically the mission No Love Lost given by Mikhail Faustin). Billy Grey talks up Jason's character and everyone downs a beer before smashing the empty bottles on the ground. Billy vows revenge and talks briefly of loyalty, mostly looking towards Johnny during this discussion. Once his speech concludes, so does the mission.