Stowing Away

M3 (regular edition) or M4 (augmented edition) - Stowing Away is a mission in Deus Ex: Human Revolution.

Primary objectives
After the cut scene with Tong Si Hung, take the sewers to Belltower's port (along the way, you will meet one final arms merchant with whom you can buy or sell). The sewers lead to a parking lot outside of a highly fortified port.

Get inside Belltower's port
There are three ways to get inside the port. Once inside, make your way to a shed in the center of the compound to retreive Tong's package.
 * The guardhouse outside the main gate has a security computer. Hacking this allows you to open the main gate. Opening the main gate will cause the nearby guards to become alarmed and to enter the parking lot to investigate. If you have the proper augmentation, it can also allow you to turn the patrolling robot inside the compound on your side; it'll make short work of all present guards.
 * To the right of the main gate (near the guardhouse) is a large crate that can be moved, exposing a hole in the fence.
 * To the left of the gate is a noodle shop. From the roof of the shop, it is possible to jump over the fence and into the compound. The roof of the crate on the other side of the fence is electrified, but the electricty can be shut off via a switch in the guardhouse.

Retrieve Tong's package from the shed

 * The first option is to punch through a weakened wall. Note that doing this will put the guards on alert; either run in, grab the package, and run out, or run and hide until they stand down.
 * The second approach is to enter the shed through the basement. There's a security terminal in the building on the right as you enter the base through the first sheds. Get inside the building, take out (via takedown or shooting) the guard inside, and disable the cameras and turrets connected to it. Then head to the stairs on the other side of the compound. Look out for the patrolling guard, double back behind the stairs to find the vent. Go through it. You'll see a breaker box; if you turn it on, it'll start up two fans that'll remove the toxic gas. Look out for the patrolling robot (or take it out with an EMP grenade or mine), climb up the ladder, look in the locker, and grab the package of C4.
 * Open window, headshot the sleeping guard, get in, then hack the access door to the storage area.

Place the C4 on Administrator Wang's desk
Once you have retreived the package, the final step is to plant it on Adminstrator Wang's desk in the compound's main warehouse. The warehouse can accessed in four ways. Once inside, make your way to the offices at the far end of the warehouse. Three soldiers patrol the warehouse floor. Two more soldiers are in a security room under the stairs that lead up the office balcony. Two more soldiers are on the balcony as well, though these two will not notice if soldiers are taken out on the floor below. The balcony also has a turret and camera, both of which can be modified and/or disabled through a computer in the security room under the stairs.
 * There is a door on the left side of the warehouse on the first floor. This door must be hacked to gain entrance. There is a guard patrolling the area who must either be avoided or neutralized. There is also a camera, but the camera's angle prevents it from being able to see you while you are hacking the door.
 * The warehouse balcony has a door. Entering through this method requires either avoiding or neutralizing the sniper who patrols the balcony. If Narhari Kahn is still alive, he can be found almost immediately inside.
 * The ledge below the balcony has a vent that can be opened and used to gain access.
 * From the balcony, the player can climb to the roof. On the roof, there is a window that can be shot out or otherwise destroyed. If you have the Icarus Landing System, you can drop down into the warehouse and potential even stun all three of the guards who patrol the warehouse floor.

To reach Administrator Wang's office, you can take out the soldiers or sneak using the ample cover. The offices can be accessed through a door or through a vent on the roof.

Once inside, find Wang's desk and plant the explosive. Note that planting the explosive triggers a cut scene that leads to Jensen's escape from the docks, so only plant the explosive once you are ready to leave. Tong Jr. can be seen, jumping on a boat, if you have the Augmented Edition.

Tactics
In fact the whole area can be cleared rather easily and without much noise, especially if you pick up a Silenced Sniper Rifle from open container in the left part of the area. Note: For an extremely easy clearout, hack the security terminal outside the dock, tell the robot to attack enemies and wait a while. When the 10 XP awards stop popping up (this may take a little while), it's safe to go in. Only the two guards patrolling in the lower areas should be left.
 * Two snipers on the roof in the center of the area (where Hong's package is initially found) and on the balcony of the warehouse at the far end of the area.
 * Two heavy guards patroling storage containers in the alleys that flank both sides of the main area. Unless you go into these alleys, the heavy guards cannot see you.
 * One Robot can be disabled from the guardpost even before you enter the area.
 * One guard near guardhouse by the gate can be shot while standing below camera, not triggering alarm.
 * Two guards patrolling the left area can be taken our while between containers.
 * One guard patrolling center in front of the camera, should be taken after camera is disabled.
 * One guard sleeping in central storage.
 * One guard by the computer in guardhouse by the gate (back to the door).

Stealth Approach
It is possible to sneak through the area (Cloaking Augmentation is recommended).

If the player has the Implanted Rebreather, the easiest path is to go through the hole in the fence to the right of the gate and hop over the fence on the right. Take down the one heavy guard, and then enter the room on the left that leads to the hallways below the outside area.

Go through some poison gas (and look out for the Roving Robot), to find a ladder that takes you right by the package you need to get. Then go back down to the lower level, back the way you came, and make your way north along the right side. You will emerge in a huge blind spot area for the two roof snipers, although you'll need to avoid line-of-sight for a roving robot (if you didn't disable it at the start).

Make your way west, when the guard on that side begins his slow way south. Hack into a security level 1 door, and make your way inside (Do not take him down when you see him: a camera may pick up his body).

Get into the large warehouse, hugging the left side. Sneak up the far left steps, ideally using a cloak across the last bit, because there's a turret with a very long field of vision in hard mode.

Then climb up the ladder to the roof, duck in an air vent on the top, and place the C4 on the desk.