As the title says, this is my first attempt at making a scenario/campaign for any system. Bit of background, I'm a long-time 40k player, I know the setting backwards and forwards, but I'm not at all confident about my writing skills. My group is no stranger to RPG's, but relative newbies to DH and 40k in general. I've made up a short campaign to help introduce the setting/system. Any criticism/feedback is appreciated. I'm putting itup here to learn how to be better at this GM'ing business.

Here's the text of the adventure so far:

The underhive of Hive Sibellus deep, old, and wild. But, to Wulfgang Krassner, it is a where he will make his fortune and restore his house. The last months of his father's life were filled with feverish planning and preparations for an expedition to the ancient Krassner family holdings, deep in this wild and dangerous area, but only two months after departing he-and the entire expedition-disappeared without a trace. Young Wulfgang was forbidden by his father to go, but five years later, the mystery of the lost expedition remains. The Krassner name has become a laughingstock among the nobles of the Hive, and Wulfgang is determined to see his family name and fortunes restored.

Now, as the last son of an impoverished House, Krassner has vowed to find his father and restore his family name, no matter the cost. To that end, he has spent the last of his money hiring scoress of mercenaries, dozens of guides, porters, and underhive experts, and has sold almost all of his remaining assets to finance this massive undertaking. He has released almost all of his hereditary servants, but as both he and his father were always good to them, many have taken up arms to follow him into the deep.

This is where the Acolytes come in, as according to Krassner family legend, in the library of their original manse is a sealed, lead-lined container. This box is said to contain a copy of the Malus Codicium, a thrice-damned tome of eldritch lore. The inquisitor the Acolytes work for, Galen Rathbone, is determined to find and destroy this book before it falls into the wrong hands, and this expedition is the best way to accomplish this goal. The Acolytes will pose as a group of mercenaries, find the box, and bring it back without tipping off Krassner--it would….inadvisable to be percieved as stealing from a man this desperate.

1. The adventure starts with a feast at the Krassner Estate, with all of the mercenaries, guides, porters, servants, etc. in attendance. In the morning, the expedition leaves with little fanfare. Close to 300 souls begin the long march down an ancillary staircase into the darkness of the underhive.

   1. A week into the journey, the scouting party (the party and 6 'Enforcers' with lasguns) are attacked by 4 Skulkers, and 8 Scum (2 with poor quality autoguns, 2 with poor quality shotguns, the rest with standard stub autos). The group is ambushed at an intersection, with some rubble (cover 10) strewn about, and a column in each corner(cover 16). The intersection is 25x25 meters, with corridors coming in at the 10 and 15 mark of each side, the columns are 4m in diameter.

      1. The scum attack from the corridor directly across, while the skulkers and shotgunners attack from the sides a few rounds in. The scum throw up scrap metal barricades behind some piles of rubble(Cover 24), and attempt to draw the group into the center of the intersection. IF the group takes the bait, the skulkers try to sneak around behind them; if not, they attack and attempt to create a crossfire. If the group wins, they find a map to a gang hideout. If they retreat, the skulkers follow them if they don't cover their trail.

         1. If the group finds the map, they can decide whether to tell Krassner about it, and encourage avoidance or attack. If they avoid the gang, there is a 45% chance that the expedition will be found and attacked. If so, see B. If the group advocates assault, see C.

      2. If the group is followed, the gang lord will send 55 scum (25 with standard kit, 10 with poor-quality autoguns,10 with poor-quality lasguns, 5 with poor-quality shotguns, and 5 with poor-quality hunting rifles) and 10 skulkers (3 with silenced autoguns, 5 with standard kit, and 2 with silenced poor-quality hand cannons) to attack the camp, located in a hastily fortified, partially collapsed tenement (doorways-cover 8, roof railings-cover 8, windows-cover 12, walls-cover 16, interior walls-cover 4) with most of the available cover removed or compromised(broken or pulled apart). What cover is available provides Cover 8. (The fountain provides cover 10) Defending the camp is the group, 35 Enforcers (15 with autoguns loaded with man-stoppers, 10 with lasguns, 5 with lascarbines, 5 with long las), and 5 Kill Squad Troopers (part of Krassner's house guard). There is a 15-meter cleared area in front of the tenement, one large entrance in the center and 2 secondary entrances on the sides. The alleys beyond the side doors are filled with rubble. (There is a secret passage in the south alley) There is a second floor with 3 balconies. The scum with hunting rifles will stay back in the access corridors, while the rest will attempt to rush the doors. The skulkers will attempt to sneak past any defenders at the south doorway, after the defenders are repulsed (will join in if the fight is going poorly).

         1. The battle starts while the Acolytes are being debriefed by Krassner's seneschal, Martin Trask.

            1. [He is a former Imperial Guard captain (use Bounty Hunter profile), with a good-quality bionic eye (Heightened Senses-Sight, +20 vs flash/blind), and is armed with a good-quality Hellpistol(Pistol (Las), Range 35, RoF S/2/-, Dmg 1D10+4 E, Pen 7, Clip 40, Rld 2Full, +5 to attack, Reliable), a good-quality Power Sword(Melee(Power), Dmg 1D10+5, Pen 6, Power Field, +5 to hit), and is wearing Best-quality Storm Trooper Carapace (All 7). Total DR: All 10. 1 Fate Point]

         2. Trask orders the acolytes to go to defensive positions, then heads to the roof to oversee the defense himself. If the attackers breach the defenses, he will sprint to the area and buy time for the defenders to fall back. He will retreat when the defenders tell him they are in position.

         3. The attackers will begin to retreat after suffering heavy casualties (more than 75% total, or more than 15 deaths in a single round)

      3. After the attack is repelled, Trask proposes an attack on the gang's base. He plans to interrogate a captured ganger, and he assigns the Acolytes the task (a Routine(+10) Interrogation test vs the scum's willpower. Need 5 total degrees of success to get location.) Alternatively, a Difficult(-10) Scrutiny test can find a map on one of the attacker's corpses. The map is better for each degree of success(frayed (1d10+5 hrs to the base) at 1, faded (1d10 hrs) at 2, decent (1d5 hrs) at 3, and good (1 hr) at 4).

         1. The attack consists of Trask, Krassner (use Dissolute Noble profile with good-quality bolt pistol(+5 to hit, Reliable) and Best-quality Enforcer Light Carapace (all 6)), the Acolytes, any survivors of the camp attack, 25 Enforcers (15 with man-stopper rounds, 10 with lasguns), and the rest of Krassner's House Guard (15 Kill Squad Troopers). The House Guard stay near Krassner and Trask, while the Acolytes and 10 Enforcers(Lasguns) attempt to sneak up on the right flank, while the other 15 Enforcers attempt the left. The survivors of the attack will attack down the middle, pushing makeshift portable cover ahead of them (converted tables with wheels attached, and steel plates bolted onto the front, cover 10). Krassner, Trask, and the House Guard will advance behind the Enforcers, and attempt to breach the gate(Trask uses a Melta charge on it). The PC's are tasked with diverting defenders from the front and-if possible-forcing a breach in the defenses.

            1. The compound is guarded by the survivors of the attack, plus 40 scum with poor-quality autoguns and 10 skulkers (waiting on the sides). The compound walls are 4m high, with crude crenelations (cover 12), and a pair of heavy stubbers guarding the gate. There are 2 scum with flamers are on either side of the gate, waiting for if the gate is breached.

         2. If the defenses are breached (either the gate or one of the sides), the defenders will fall back to a fortified building in the rear of the compound(walls:cover 16, windows:cover 12, doorways:cover 8, interior walls:cover 4)). The building is 3 stories, with a large stairwell in the rear (2 small ones near the front corners, busted out. A routine(+0) climb test can scale these).

            1. The first floor is guarded by the scum fleeing from the outer wall, with 5 Scum with shotguns scattered throughout.

            2. The second floor is guarded by 20 Recidivists(10 with autoguns, 8 with shotguns, and 2 with hunting rifles), and 10 Scum(standard)

            3. The third floor is the ganglord's sanctum, with 10 Recidivists (6 with shotguns, 4 with autoguns) guarding it. There are 2 rows of armored desks (cover 12), and an ornate(albeit shabby) desk in the back center (cover 14). The ganglord is here as well, roaring orders at his men. The gang lord uses the Bounty Hunter profile with 2 hand cannons with man-stoppers.(assume 2-weapon wielder, ambidextrous, recoil gloves)
               

I think the background is good and the mission makes sense, and it will interesting to see if noble catches the players taking the book!

I think you have good detailed battle plans for the fights against the scum, but why are the scums trying to attack a 300 man force, instead of just letting them pass? What it is that the scums know that drives them to attack the noblemans forces? Do they know about the book, and are they afraid of what will happen if someone uses the book in their territory, maybe the after the battle and the scum leader is interrogated the nobleman learns about the book, putting the players in a dilemma?

A good majority of the expedition (say half to 2/3) are civilians-so they're either unarmed or poorly armed. The gang did not know this at first, and simply thought that it was a small group(we played the first scenario already and the mercs with the PC's got slaughtered. 2 of the scum escaped early and got the gang together to go fight). I also am going to have a cult in the Krassner Manse that worships the book, and have almost cracked the seal on the box. They're forcing the gang out of its territory, which is the reason they're willing to press the attack once they realize it's NOT a small group.