- The Maggia (Mentioned)
- Count Nefaria (Luchino Nefaria) (Mentioned)
- Aleksander Lukin (Mentioned)
- Yashida Clan (Mentioned)
- Gorgon (Tomi Shishido) (Mentioned)
- The "Fat Man" (Mentioned)
- Thor (Thor Odinson) (Mentioned)
- Wasp (Janet Van Dyne) (Mentioned)
- Black Widow's Gauntlets
- Captain America's Shield
- Captain America's Uniform
- Mockingbird's Battle Staves
- Hawkeye's Suit, Bow, and Trick Arrows
- Grim Reaper's Scythe
- Iron Man Armor Model 8
- Ant-Man's Suit
- Vibranium Energy Daggers
- Satan Claw
- Cosmic Cube
- Doomsday Chair
After crashing a clandestine meeting between Grim Reaper and MODOK in his hunt for Black Widow, Hawkeye is reprimanded by Stark and Nick Fury. While Clint says SHIELD isn't moving fast enough in locating Natasha, Fury orders Hawkeye and the Avengers to stick to hunting down super-villains, and not interfering with operations against the terrorist organization. Stark, shockingly, agrees with Fury, leaving Clint angry. He says he'll find the Black Widow on his on, and that he's ready to call it quits with the Avengers.
Before leaving the Helicarrier, Captain America and Black Panther agree to help him, knowing that take on HYDRA alone is a suicide mission. Also ready to help Hawkeye is operative Bobbi Morse, the one saved by Hulk, now codenamed "Mockingbird". After Hawkeye's imprisonment and later departure, SHIELD promoted her to take his place in thier their special ops team. Accompanying the three aboard the Quinjet, they reveal that they know she's really come along to be a mole for Fury. She blows her cover, but is still willing to help them if it means taking the fight directly to Baron Strucker in order to capture Black Widow.
Hawkeye and Mockingbird attack Grim Reaper head on, after following him with a tracker planted on by Hawkeye during last encounter with him. They allow themselves to be defeated and captured, while Cap and Panther follow the HYDRA ship in the Quinjet. Grim Reaper, however, cloaks the ship as they approach HYDRA Island. As such, the Quinjet loses Hawkeye's signal. They report back to Pym and a furious Stark, telling them they lost Hawkeye and a SHIELD agent.
At the island fortress, Grim Reaper presents the prisoners to Baron Strucker, Viper, and Black Widow, to make up for the fact that MODOK wants an increase in the payment for the "Cosmic Cube". Strucker wants to immediately kill the two, but Viper persuades him to let them live, for a ransom on an Avenger would be profitable. In the dungeon, Bobbi tells Clint that his vendetta against Natasha has endangered them and his teammates. Just then, Black Widow tries to privately speak with Clint, but he refuses to listen. He swears that he'll never stop hunting her, that she will pay. While Bobbi states that Natasha really must of got under his skin, he then proceeds to bust himself out, freeing Mockingbird next.
Meanwhile, in the headquarters of AIM, MODOK is informed about the status of the Cosmic Cube. Originally, they never intended for the project to work, it was merely a smokescreen to swindle money from the HYDRA organization. But upon further investigation and research, it appears that the Cosmic Cube is an impossible success. MODOK proclaims that this changes everything.
The two, however, are faced down by over 140+ HYDRA agents when they try to attack Strucker and Black Widow. They manage to hold their own, but they become outnumbered. Hawkeye tells Mockingbird to go, he'll try to hold them off for her escape. He then makes a suicidal assault upon the HYDRA forces, at which point Captain America and Black Panther arrive, smashing through the glass ceiling. Apparently, Hawkeye's signal was reactivated, which allowed them to find HYDRA Island. The four smash the HYDRA soldiers, and manage to take down Viper. Baron Strucker proceeds to activate the Island's self-destruct sequence.
Black Widow begins to escape with Strucker, so Hawkeye pursues them while the other three take care of Grim Reaper. He viciously fights with Black Widow, until he is fully immobilized from the waist down. Strucker congratulates her on her performance, stating that he almost didn't believe her sincerity on double-crossing SHIELD. Black Widow demands that they escape now, but Strucker decides to stay, long enough to drain the life out of Clint. Just as he is about to kill Hawkeye, Black Widow blasts him from behind and knocks Strucker unconscious.
Natasha remorsefully apologizes for her betrayal, then escapes from the base with Strucker. Cap and Panther manage to find Clint in time, and all three escape. Nick Fury contacts them and helps them get out in time, just as HYDRA Island explodes. Safely on board the Helicarrier, he yells at the Avengers once more, only this time threatening to use the full might of SHIELD to shut them down if they interfere in his operations again. While arguing back that they helped capture Grim Reaper and Viper, the Avengers agree to stay out of SHIELD matters, then leave. Panther comments that Stark has some words for them as well upon their return, but Hawkeye is more puzzled than ever about the status of the Black Widow. Is she a traitor, or deep undercover.
Back in Manhattan, Natasha manages to convince Strucker that Black Panther was the one that attacked and incapacitated him. Just then, an A.I.M. ship arrives, with MODOK and his top scientists. They return all the funds given to them by HYDRA, and "apologize", claiming that the Cosmic Cub project has failed. A.I.M. leaves, leaving Black Widow bewildered as to what just happened. Strucker immediately knows that something is wrong with what just transpired, he knows MODOK is lying!
Meanwhile, across town at the secret underground base of SHIELD, Fury and Mockingbird are studying a shocking find. Mockingbird asks what it means. We're then shown the body of Viper, revealed to be a undercover Skrull agent , to which Fury responds that "It means we've gotta Big Problem".
- The command code used by used by Baron Strucker; Fenris is the codename used by his twin children.