Surveying The Score
Send any character to the back room of the Vanilla Unicorn strip club to trigger this mission. Trevor is recommended to start the mission in order to get the full cutscene. To reach the room, enter the strip club and go through the curtains under the "Premium Lounge" sign. Upon reaching the back room dressing area, turn right and go through the door at the end of the corridor. This triggers the opening cutscene: Trevor lays out his life plan, which includes busting their old partner Brad out of it prison. Lester joins the crew to discuss "the big one" - the Union Depository Bank. As the team leave the club, you 'meet' the former owner of the club, Leon.
You now control Michael, get into his car and wait for Franklin to get in the car as well. In the meanwhile, Lester joins Trevor in his vehicle heading for the air field in Sandy Shores. A clock will appear in the lower right corner of the screen, starting at 12:00 noon. Keeping control of Michael, follow the yellow route to the destination marker on San Andreas Avenue, directly across the street from the Union Depository. Be quick about it as the clock is ticking. When you arrive, follow the on screen instructions to take a closer look at the entrance of the bank. Listen to the conversation between Franklin and Michael, at the end of the conversation a new objective will appear.
Follow the Yellow route to Alta Street around the corner and park in the pullout next to the Arcadius Business Center to check the Depository's back entrance. After viewing the lightly guarded gate, Michael reports to Lester. After which you automatically switch to Trevor.
As Trevor, follow the Yellow route to his Sandy Shores Airfield in Blaine County. When arrive at the destination, get out the vehicle and into the helicopter and wait for Lester to join you. Lift off and fly after the yellow dot on the map marking Murrieta Heights. When you arrive a cutscene will play: Lester points out the two convoys crossing the Del Perro Freeway on the Innocence Boulevard overpass. Lester starts filming the vans so you can mark their route and find a good ambush point.
Stay with the security vans as they turn right on the Popular Street, left onto Capital Boulevard running across the Los Santos River, and then right on to Little Bighorn Avenue. At this point , the route runs underneath the Olympic Freeway and turns left on Adams Apple Boulevard. The van takes the next right onto Sinner Street, then drive past San Andreas Avenue and turn left on to Swiss Street. Then they disappear into the tunnel.
The tunnel runs in a straight line for two blocks, so continue in that direction until you see the vans emerge at the other end (or follow them through the runnel to achieve 100% in this mission). When they turn left on Alta Street, they reach the spot where Michael and Franklin are sitting in their car. The both vans turn into the Banks rear entrance , and this triggers a quick cutscene: the lead driver flashes his ID card to the gate guard who lets the vans through.
All that is left to do now is find the construction pit in the parking lot behind the bank. Once you spot it, follow Lester's instructions to fly over the hole and drop down close so he can capture some footage. You must hold the chopper in place for a few seconds until Lester lets you know he has got what he needs. You can now complete the mission as either Trevor or Michael.
If you switch to Michael, follow the Yellow route back to Franklin's house up on Whispymound Drive, Vinewood Hills. Michael drops off Franklin and the mission ends.
If you remain as Trevor, follow the yellow blip on the map back to Trevor's airfield in Sandy Shores. On the way Lester and Trevor discuss some of the heists probable logistics. When you land on the destination marker, Lester exist the chopper and the mission ends.
 Conditions for failure
- You die
- you run out of time
- Perfect Distance: Follow the security vans without being warned on your distance to them.
- Cavity Search: Find the construction pit in the parking lot behind the bank within 20 seconds.
- Under the Bridge: Fly under the bridge while following the vans.
- Tunnel Flight: Fly through the tunnel while following the vans.
- Mission Time: Complete mission within 11:00.