Read Prima's free inFAMOUS: Second Son walkthrough.

This mission begins right after you save Reggie on the bridge. Run forward to the D.U.P. checkpoint and have your hand scanned. When things go badly, melee the closest enemy and take cover. Your Smoke Shot has a limited range, so be sure to Smoke Dash between the two-piece barricades and take out the D.U.P. soldiers when you're close. If you run out of smoke, grab some from a nearby vehicle. If none of the vehicles are smoking, shoot them and then replenish.

Tip: Your Smoke Shot has a limited range. If your crosshairs turn red while locked on to an enemy, he is within range. If the crosshairs remain white, they are out of range. Don't waste your Smoke Shot if you're out of range.

When everyone is down, check for enemies that you can subdue and civilians you can heal. This will help your Good Karma. 

Your main objective is the Mobile Command Center, marked as the star with the square around it on the radar. Approaching it at street level makes for an intense fight. Instead, find a nearby vent to reach the rooftops. Along with a tactical advantage, you'll also find plenty of chimneys to replenish your Smoke if you run low.

Head for the Mobile Command Center where two nearby buildings overlook it. Stay up there and spend some time taking out the D.U.P. forces below. From this position, they are fairly easy to take down. Just keep ducking if things get too hot. Even if you absorb the smoke from one of the chimneys, it will reset a few minutes later and allow you to absorb it again.

When all of the D.U.P. forces are down, jump to ground level and subdue anyone who isn't dead. Look near the Mobile Command Center for a cage that houses Conduit suspects and open the door to free them. Approach the Mobile Command Center and use your Smoke Shot to destroy the panels on either side. With the panels exposed, shoot each of them again until they turn dark and the main power core is visible on top. Jump on top of the Mobile Command Center and destroy the core.

Destroying the core will cause backup to arrive. Along with some regular D.U.P. forces, there's also a big D.U.P. agent with what appears to be a mini-gun. Use the vents to get back to the rooftops where you can avoid his attacks. Top off your Smoke and then focus on taking out the regular D.U.P. forces, leaving the big guy for the end.

When the final agent is down, approach and finish him off. If you wait too long, he'll get back up and you'll have to defeat him one more time. When he's down for good, try and absorb his concrete powers to complete the mission.

Tip: Even though the mission is over, make sure you collect all the Blast Shards in the area. These, along with security camera locations will be displayed on your map. Blast Shards are used to upgrade Delsin's powers.