Hey there,

This shall be my first time GMing of any sort really but I feel i have a good hang of the rules and mechanics of Deathwatch. One big advantage is that I don't have to have every single mission be an integral, story filled adventure, many can be individual missions that fit a variety of mission archetypes, such is the role of a Deathwatch Kill Team. Despite this I have so far planned a story arch that can be expanded (and will need to be) and altered if needed depending on personal preference as well the actions of the players. I'll try to run through the key elements of it here as best as I can but as its still early-ish in planning bits may be slightly stitched together as Ideas were found mid sentence at times

The beginning mission will be largely the same as the 'Extraction' pre made mission in the core rulebook with the team having to find and secure both the Magos techpriest as well as the dataslab it protects. The only main difference I am adding is that at the initial stage of the mission, the team will play as the small imperial guard contingent said to be on the planet. This will act as a kind of tutorial just to ensure people are pretty comfortable with the different mechanics, especially as they will have less complications with a simple gaurdsman. By the same token, this will also act as a comparison for them when they finally get to use their own guys and can see then how powerful they are. Once the techpriest and/or dataslab is returned then it will be given to the science labs and can be used later down the line as a means to find tyrannid based missions.

Now begins the true story mission arch. This wouldn't be the next mission, but instead can occur at any point. Before this begins there would be talk or some kind of acknowledgement of an incoming Librarian around the watch fortress, with certain unclear rumors about a suspicious past involving the forces of chaos. Closer to the mission, this Librarian, Corvus, would be introduced to the watch fortress although not necessarily to the kill team directly.

Later the kill team would be assigned to a mission involving a small colony/ tribe etc.. (doesnt matter as such, although it could be cool for this to take place on a feudal world), that has not been heard from for a relatively long amount of time. The exact reasons can sound pretty far fetched really, such as a 'signal' no being sent from a world that doesn't even have that technology as there are other reasons for this mission's existence not known to the kill team yet. On the orders of the watch commander himself, Corvus joins your squad. You are told a contingent of imperial guardsmen should also be en route to aid you, however you will arrive first. When they are sent to the planets surface they will find a village with corpses strewn everywhere (medicae tests or the lie would show the injuries to be self inflicted by the people, both to themselves and each other). As the killteam advance the quantity of bodies would increase and show more suggestion of taint from the warp. They may find some people alive, but unable to communicate. Further on still they would encounter individuals or even a horde of crazed, berserker like villagers, perhaps buffed by some warp corruption to make it a slightly more enjoyable fire fight. Eventually they would find a central point in the village in which theres an empty podium and multiple piles of corpses. Upon reaching the podium daemons of some variety would emerge from the corpse piles and a fight would go down.

Once this is done and the location is secured your 'backup' finally arrives and you begin to try and discover what occurred here. Either by you own ability or help from an npc, a pict sensor is found and upon analyzing its data whilst still on the planet, you are shown a horrific sight. The exact description will be minimal to add to the mystery/ horror (ideally ) but it shows images of a chaos sorcerer planting an orb on the podium and proceeding images of the warping it causes to the inhabitants of the village. I may choose to test the players willpower and give corruption points if fails are bad, but they will then be given the ultimatum of executing or leaving the gaurdsmen alone, who have also witnessed this as it is a grave example of heresy and would I believe massively corrupt their more feeble minds.

Once this has been solved you return to the watch fortress and speak to the commander. He tells you that there were suspicions of chaos on the planet, hence why Corvus was sent with you and why they didnt risk revealing this initially. He says Corvus is an expert of the warp and chaos, and thus you should speak to him.

Corvus will then speak more about this kinda thang, including an explanation of his past, which the group should have heard rumors about. In short the rest of his old kill team was decimated by a chaos force, perhaps a daemon prince even, but he was left untouched, suggesting some form of chaotic favor. This explanation should go someways to dispelling doubt over his purity, but not entirely, doubt is good here. He then speaks of the orb seen in the pict sensor feed, speaking of some old legend of a 'warpstone' a UNIQUE object that acts as a focus for the warp, thinning the veil between reality and the warp around it, allowing those who wield it 'unimaginable power' and that kind of thing.

Later on down the line, another mission like this will occur, however the location is closer and ultimately, the team will capture the orb (attempts to simply destroy will either causes damage or maybe even causes daemons to summon). A cultist could also be found alive and interrogated, revealing that the powers of chaos plan to sue the stone to corrupt and initiate vast quantity of new soldiers within their ranks whilst depleting the numbers of those they take from.The exact details of this mission can vary really as it is the end point, of capturing the orb that is important. Once it is retrieved then there can be confirmation that this was indeed the warpstone Corvus spoke of, and the kill team is honoured for removing such a strong threat from the hands of chaos. The orb is kept within the watch fortress to be studied further.

Once a few lesser missions have passed, the team are informed that the adeptus mechanicus sector of the watch fortress have been studying the chaotic orb and have been able to register the warp signature of the orb to a much greater degree of accuracy compared to what they were able to detect when they traced it during the previous two missions it featured in. As a result of this, the fortresses astropaths/ detectors etc... (whatever works) have located a strange signal that shares some similarities to the signature of the orb, something that isnt too significant except for the fact the sector of space was thought to be empty.

Again the details of this are not nailed down as of yet, but the key part of this is for the team to find a derelict planet in this location, consisting almost entirely of a large mining factory intermingled with a large desert that has reclaimed parts of the planet wide construct. Tyrannids could be introduced as the enemy. Ultimately the team discover the source of the signal, although it is behind an enormous door, that has the double headed eagle of the imperium adorned upon it. In the room before it they find a huge database, with largely corrupt unreadable and censored data, however one way or another they will acquire its message, that the mining factory had once found these strange stones that seemed sensitive to their surroundings and gave of an odd aura, information of some illness throughout the mining site that was finally accredited to the strange stones upon the intervention of the Inquisition. The planet was then taken over by the Inquisition and beyond this the records are entirely retrievable. Again by means that I will have to think of, the team manage to open the huge doors, behind which are rows upon rows of shelves, all holding stones that look exactly like the warp stone the team believed to be unique.

From here my ideas arent fully fleshed out but with this knowledge the fortress dedicates itself largely to finding other warpstones. A key point will be finding a warpstone signal on a large agri planet associated with a huge important hive world so the team moves in to remove this threat as it could corrupt an entire planet, one that I could say is key to a certain chapters recruitment. Within this task however I want them to be held up by the imperial commander of the planet, who is secretly ,or perhaps obviously at this point, corrupt and aiding chaos. He may even use false evidence against the kill team, such as if they decided to kill the imperial guardsmen who saw the pict feed images mentioned in the earlier mission, in an attempt to have them killed.

As i say more info in needed for these later missions but i feel pretty confident that the story has enough potential to be interesting. Any thoughts and ideas are more than welcome :3