In Grand Theft Auto V, the mission that begins with the Union Depository heist is “The Big Score”.
It is the final major heist planned by Michael De Santa, Trevor Philips, Franklin Clinton and Lester Crest. Their target is the Union Depository in Los Santos, which stores a vast reserve of gold bullion. The crew can approach the operation in two ways: a direct “Obvious” plan involving heavy equipment and a large firefight, or a more elaborate “Subtle” plan using disguises, tunnels and a staged transport operation.
The Big Score is the culmination of the game’s heist structure and follows extensive preparation missions. Its outcome also helps determine the protagonists’ financial rewards and leads into the ending choices presented to Franklin.
The Bureau Raid is a separate operation against the FIB. The Merryweather Heist targets military cargo, while The Paleto Score is the earlier robbery of a rural bank. All are major missions, but only The Big Score targets the Union Depository.