It takes a minimum of seven missions to open up the bridge leading to the western half of the Vice City map. The player must complete the sequence of core missions that advances the story until the "Guardian Angels" mission has been completed.
The player must start this sequence by completing four missions for Ken Rosenberg. Along the way, the missions for Colonel Cortez become available. The third of these missions is "Guardian Angel." After it is complete, the Ricardo Diaz missions become available, and the player is able to access the formerly locked western portion of the Vice City map.