I thought I would go ahead and start this thread for GM's to take, use, or change any ideas we all have to fit their game. Afterall I like to believe that GM's are some of the most creative people around. Enjoy.

Hook - Squad gets sent out to a colony that hasn't contacted the Imperium in over a month. Under suspicion of xenos threat the squad gets sent out to investagate.

Line - The colony is entact with slight scoring on some houses. The colonists are all there and going about everyday bussiness. Under questioning the govenor of the colony explains that they had a small run in with alien creature threat but disposed of them with the only causaulty being their comm array. Lacking the materials the colony was waiting for Imperial contact to get it fixed. The squad may send its Tech Marine to assist in this while the rest of the squad looks around. If questioned the other colonists may seem nervous. The comm array is delayed due to materials going missing and subtle sabotage. The squad may accept a invitation by the govenor to attend a feast / festival in their honor.

Sinker - On that night the citizens attack and try to subdue the squad, because they are converts to a Tau envoy that showed up to save them from a attack. Because the Tau were there for them when the Imperium wasn't these colonists have been feeding a Etherial Imperium information and was waiting to lure a Marine squad to their colony for the Etherial. The Etherial wants samples of the Space Marine Gene Seed, for what reason. Thats your choice.