- "I need another favor. Some documents are about to change hands that would be very useful for me. Security system plans - seems we both have eyes on the same prize. The exchange has been set up at a construction site on top of a skyscraper in Downtown so you'll need a helicopter. Bring the briefcase to the warehouse. Make this happen and I won't forget it."
- — Description
There is a security system plans exchange taking place at the top of Mile High Club construction site in Downtown Los Santos (the same place where the mission The Construction Assassination takes place). Lester is interested in the plans. When one of the players has collected the briefcase, the team needs to deliver it to Lester's warehouse in Murrieta Heights.
- Steal the briefcase.
- Deliver the briefcase to Lester's warehouse.
- A helicopter is required.
- It is advised for the team to land at the top of the Maze Bank Tower building to have a perfect angle for sniping the plans' protection men.
- Alternatively, the players can shoot from a hovering helicopter, however this involves more risk.
- If a player has a Buzzard Attack Chopper (or alternatively the Savage or Hydra) available, the top level and open area of the lower level can be easily cleared with rockets, however care must be taken to avoid targeting the men close to the briefcase as destroying it will fail the mission.
- Once all the men on the roof are dead, the team enters their helicopter again and lands it on the building where the briefcase is.
- More men will be in the lower floor protecting it.
- Once the briefcase is secured, an enemy helicopter with gunmen will approach from the northeast and give chase to the warehouse. If the players end up on the ground (i.e if their helicopter takes too much damage and cannot make it to the warehouse) further NPC enemies will give chase in Grangers.
- Along with Sinking Feeling, this is a mission with no respawning if one of the players gets killed (presumably because a respawned player will be on the ground and have no way of getting back up to the briefcase).
- The mission's name is a pun - the phrase "High Priority Case" would usually refer to a court case, but in this respect it's referencing a briefcase.
- Helicopters are scarce around Los Santos, as Lester will not provide a helicopter to spawn. This makes the mission incredibly difficult to complete unless one already has a helicopter bought from either ElitasTravel.com or Warstock Cache & Carry.
- Merryweather helicopter pickups are available at rank 30.
- Helicopters do spawn at the Higgins Helitours helipad at Puerto Del Sol, but they might not be there on the first visit. If a helicopter is not there, drive back out and turn left towards the marina, turn round and come back. If a helicopter is taking off when you get there, drive up and wait as it will usually hover for a moment and land, unless you park on its designated landing pad or do something aggressive to scare the pilot off.