This mission starts in the south central portion of the Neon. Your first task is to recharge a cell phone tower in the blacked-out area of town just west of you. Find the tower on the roof where you're starting and knock it down, then cross the tower to the wire and then up to the roof with your objective. Charge up the cell tower.
Enter the manhole[edit]
Follow your objective marker across to the next roof and an emergency generator you can use to charge up. Cross back over to the previous building and find the long wire that leads from the west side of the building to a high building a block away. Go to the corner of the roof and find the turret truck on the train tracks. Rain Lightning Bolts on it until it blows up, then take out the Reaper who had been manning it.
You can then jump down to the beam running over the track and cross quickly (under heavy fire) and leap to a roof where you'll find another generator. You'll need to move carefully around to the objective marker on the west side of the island. The streets are crawling with Reapers and there's another turret truck on the street that borders the water.
Your objective is a manhole in the middle of a street. If you wait around on a building, taking the occasional shot at a Reaper below, eventually the whole mob will gather below you. Thunder Drop on them and then make a run for the manhole. If you're taking too many hits, look for the gas station at the intersection west of the manhole. If you lure a few there and then turn and blow the place up, you can rid yourself of a lot of heat very quickly.
Get your grenades[edit]
It's time for another sewer run, pretty much just like the last one. The platforming elements are a little more stringent this time around, but nothing you can't handle. (They don't get really hard until later.) You won't encounter any Reapers until after you re-energize the transformer and learn the Shock Grenade power.
Keep going, blowing up the boards blocking in your way when asked. Keep an eye out for circuit breakers and other sources of electrical energy to recharge your meter. After the wall you blow up, you'll see a group of Reapers sitting around a campfire. Throw a grenade from a long distance away (before they see you) and you can probably take them all down with one shot.
The next trap is three machine guns – one in front and one to each side. There are generators near the intersection, so run up to them and take cover behind one. It will keep you charged up while you lob grenades at the turrets. Once all are out, advance, keeping an eye out for the two kamikaze bombers that will run at you right in front of the substation. Take them down from a distance or you're going to be starting over from the last checkpoint.