Attack on the HYDRA Research Base

"Report to your stations immediately. This is not a drill. We are under attack. We are under attack."

- HYDRA Soldier

The Attack on the HYDRA Research Base was the final confrontation between the Avengers and Wolfgang von Strucker's HYDRA branch. The attack successfully ended the War on HYDRA.

Background
During the attack on the Arctic HYDRA Research facility, Director Phil Coulson downloaded important files and data about HYDRA's activities. It contained the location of Wolfgang von Strucker and his illegal experimentation on human subjects. These files revealed also the presence of the Scepter. After the battle and destruction of the Arctic HYDRA Research Facility, Coulson sent the information to Maria Hill during a private conversation and asks her to bring the Avengers to attack the Sokovian HYDRA fortress.

Later, the Avengers agreed to launch an surprise attack against the HYDRA base and assure to foil HYDRA's plans to dominate the world.

Attack
The Avengers arrive in the snowy terrain somewhere nearby the HYDRA Base. Black Widow drives a jeep with Hawkeye standing on the backseat, taking out the HYDRA soldiers one by one. Iron Man tries to fly directly into the base, only to get repelled out, by the advanced shielding that the base contained. It is revealed by J.A.R.V.I.S. that the shielding around this base is the most advanced among the others. Inside the main building, Baron Strucker is briefed on the situation: the Avengers commenced their attack at the edge of the forest and the soldiers panicked. Strucker orders the staff to send the rest of the tanks and soldiers and telling to them focus on the weaker ones, as to prevent them from scattering.

He discusses with List the amount of research they've done, the latter tries to convince him to send the twins, but Strucker refuses, saying they're not ready for battle. He reaffirms his confidence in containing the Avengers.

The soldiers begin to fire at Iron Man, and the shells start to hit the town, leading Iron Man to send the Iron Legion to evacuate civilians. After some resistance from the local population, the Legion successfully evacuates most of the area.

Shortly afterwards, back at the base, Strucker delivers a speech to his people, telling them that they will continue to fight and will not surrender. Privately, he tells List that he plans to surrender, and asks him to wipe all data from the base, saying that if they'll hand all weapons to the Avengers they might not realize what else is left at the base. Before List can take any action, both of them realize that the twins went missing.

Back at the forest, Hawkeye is trying to destroy another Hydra bunker, and is encountered by Quicksilver. Quicksilver used his super speed to activate the turrets on top of the bunker, injuring Hawkeye in the process. Quicksilver then engages with Captain America, using his speed to his advantage. Captain America relays the information to Stark about the arrival of powered people on the battlefield.

Breaching the Facility
Shortly afterwards, Iron Man successfully deactivates the shield around the facility by destroying the power source in the north section.

He breaks into the facility and quickly dispatches the remaining agent and shoots List with an energy beam before the latter could wipe out all data. Stark leaves the armor and tasks J.A.R.V.I.S. with making a copy and sending it to Hill back at H.Q.

Back at the forest, the Hydra soldiers surrender. Romanoff approaches Banner and touches his hand, singing, which triggers him to go back to normal.

Inside, Stark realizes the facility holds more than just research, and, with J.A.R.V.I.S.' assistance, manages to find the secret passage to the underground. Elsewhere, Captain America finds and confronts Baron Strucker about the scepter and the human experimentation going on in the facility, only to be attacked by Scarlet Witch, who quickly flees the scene. After receiving no answer, Rogers quickly subdues Strucker.

Underground, Stark arrives at the lab, housing Chitauri armor, weaponry and even a Leaviathan, all recovered from the Battle of New York. He finds the scepter, but before he can grab it, he is hexed by Scarlet Witch, who managed to sneak up behind him. Suddenly, his worse fears come to life. The Leviathan starts to move and flies over him, he turns around and realizes he's in the Chitauri Space. His teammates in front of him, all dead. Steve Rogers briefly opens his eyes, telling Stark that he could have saved them all. He looks up and sees a wormhole to Earth, with several Leviathans, Chitauri and other beasts flying through it, ready to attack.

He wakes up from his trance, summons his armor gauntlet and grabs the scepter.

Aftermath
Most of the HYDRA soldiers were either killed or deserted on the battlefield. The Avengers transport Baron von Strucker to a NATO prison and retrieved the Scepter. Stark is left affected by the visions he had seen, and is even more adamant about finishing the Ultron project. After these events, the HYDRA research base is abandoned until Ultron returns to create a new body for himself and take over the sentinels created by Hydra.