"The Fan" was the 13th story mission of Infamous: Second Son.
Delsin's first task here was to sabotage four beams underneath an overpass in order to trap the incoming D.U.P trucks. Once done, Delsin engaged in combat with the forces within a large dust cloud. He the went to search the buses the D.U.P were escorting. Before he could actually do so, a helicopter comes spiraling out of the sky and crash lands near Delsin, temporarily knocking him unconsicous.
Upon waking up, Delsin discovered the buses had left. Using the tracking app he got from Eugene, Delsin had to get to a higher vantage point and track the signal of each bus. Unfortunately, all three of the buses were empty, but Delsin managed to stumble upon a bizarre scene of angels fighting the D.U.P forces.
Before you can start this mission, you must destroy the nearby D.U.P Mobile Command Center in the Lantern District. After it's destroyed, make sure you absorb any blast shards that appear; they can come in handy for any new powers you may need for this mission.
Once you begin the mission, your first task here is to destroy the four beams supporting the overpass. Once done, wait for the D.U.P trucks to show up. You must then confront them and take them out within a large dust cloud. After clearing them out, head to the buses the trucks were escorting and investigate by clicking on the track pad. A helicopter will then crash near you. Afterwards, you'll wake and see the buses have left. You must get to a high vantage point and use the app on your phone to track the signal of the first bus.
The lower the numbers get, the closer you are to getting the signal. Once you get to the first bus, clear out the D.U.P forces, then search it. Unfortunately, it'll be empty, and you'll be attacked by more D.U.P agents. Take them down, and then get back onto the rooftops to get the signal on the second bus. This bus will also be empty, but you won't have to deal with any enemies. Ascend back to the rooftops to begin tracking the final bus. When you find it, you'll discover a somewhat bizarre scene of action — a horde of angels fighting against the D.U.P forces. Go ahead and intervene to clear the area out in order to search the bus. Once again, it's empty, and the mission will end here.