Synopsis
This issue runs parallel to the Siege: Cabal 1-shot with some shared scenes with extra info.
The whole issue claims to be a flashback dated 2 days ago. I believe the timestamp is supposed to be relative the the day of the Siege of Asgard.
It's a meeting of Norman Osborn and his Cabal (currently Doctor Doom, Hood, Loki and Taskmaster) in Avengers Tower. (Siege: Cabal has more of the earlier part of the meeting.) Doom threatens to kill Osborn unless he produces his ally the Sub-Mariner. (Namor betrayed the Cabal in the Utopia crossover with the X-Men. But Osborn doesn't *have* him to produce - Subby is living with the X-Men on Utopia island.) So Osborn calls in his secret weapon the Void who blasts Doom through a wall.
Next thing we know Osborn as Iron Patriot is calling Victoria Hand to evacuate the whole Tower. On various screens she sees flying robot bugs swarming through the building. (Reading S:C tells us that Doom was actually a robot whose destruction released the swarm.) She tells the Dark Avengers present (Bullseye, Daken, Moonstone and Venom) to head for the quinjet on the roof. We see IP protecting himself from the bugs with a forcefield but unable to counter the threat. He tells Void that his presence mustn't be made public, so he orders him to leave and turn into Sentry/Bob Reynolds.
Hand and the DAv reach the roof where they are joined by Sentry carrying his wife Lindy Reynolds and asking what's happening. (I believe Sentry is unaware of his actions as Void working for Osborn.) He ignores Victoria's order to stay and get in the quinjet, but heads off to find Norman. Bullseye also ignores orders and commandeers a helicopter to take Lindy away. Ms Hand gets the others in the quinjet and tells them to follow him, but by the time Daken and Moonstone have stopped squabbling over who should fly the plane they've lost him and don't know how to contact him.
Bullseye has his radio turned off anyway as he flies the chopper out to sea. He tells Lindy he's taking her to a mid-ocean safehouse. He tells her he's Hawkeye (his cover-id on the team), but soon his chat turns sinister. He leaves the 'copter on autopliot as he wonders what Sentry sees in her (she's not been looking after herself lately). He says everyone knows Bob is mad, and marrying *her* proves it. When he's got her scared he strangles her to death, dumps her body in the waters and heads back to land. (Last issue Osborn told him to kill her when he gives the signal - but I don't think Bullseye waited for any signal.)
Back in the Tower Sentry rips the robot Doom apart and smashes the 2 halves together. There's a large explosion and the bugs all go inert. Emergency over.
The quinjet and chopper return to the roof. The missing team member Ares is now present. Sentry is with them too and asks where is wife is. Bullseye claims that Lindy committed suicide by jumping out - she said she was scared of Bob/Sentry/Void. Sentry turns into Void and attacks him. Iron Patriot and Ares try to hold him back. Bullseye swears he wouldn't dare kill her, and if he did he wouldn't dare come back. Sentry calms down and asks where it happened. Bullseye says somewhere over Jersey and Sentry flies off to look for the body.
Osborn tells Hand to send a HAMMER team to help in the search, and to inform the White House this was a Latverian terrorist attack. As the dust settles Bullseye and Osborne exchange a glance, and Victoria suspects that Bullseye was acting under orders.