Thunderbolts full plot

Val is under federal investigation for illegal supersoldier experiments, so she sends Yelena, Walker, Ghost and Taskmaster to take out her secret research labs all over the world.

In-between missions, Yelena visits Red Guardian and talks about the growing “void” inside of her. He runs a limo rental service now.

Val sends the four to a desert base so they will also kill each other and tie up all her loose ends. Red Guardian finds out while chauffeuring for Val, while her assistant Mel tips off Congressman Bucky.

At the base, Ghost immediately headshots Taskmaster and loots her gear. The surviving three run into Bob, one of Val’s failed test subjects, and they all team up to survive when they realize Val wants them all dead. Yelena bonds with Bob.

Val sends soldiers to the base, so Bob sacrifices himself to distract them while Red Guardian rescues the others. Turns out Bob actually has superpowers and survives, so Val orders him captured and delivered to the Avengers Tower, which she bought and rebranded “the Watchtower”.

Bucky rescues the group from pursuing soldiers and recruits them to take out Val and rescue Bob. Red Guardian names them “the Thunderbolts”. Meanwhile, Val convinces Bob to become the Sentry by acting motherly and claiming she can make him the world’s most beloved superhero.

The Thunderbolts attack the Watchtower, fight soldiers and confront Val, who sends the Sentry after them. He easily defeats the team, but refuses to kill them. When Val presses for him to do it and begins insulting him, the Sentry turns on her, so she triggers a kill switch she built into his suit.

The Sentry survives, snaps and turns into his evil the Void, then creates a literal void over the Watchtower and begins pulling people in it, trapping them in suspended animation eternally reliving their worst memories to feed off their suffering.

The Thunderbolts save a lot of people from the collateral damage of the Void’s rampage, then Yelena jumps into the void to save Bob, but gets trapped in her memories of the Red Room until the others jump in as well and break her out.

The team helps each other conquer their fears (except for Bucky, who has already vanquished his demons) and reach Bob, trapped in memories of his abusive childhood and meth addiction. Yelena manages to get through to him, and he pulls the Void back inside himself, undoing the void above the Watchtower and freeing everyone trapped in it.

The team goes after Val, but she has already called a press conference where she introduces them as the New Avengers and presents herself as their benefactor. They decide to play along, blackmailing Val into financing them and setting up a base of operations in the Watchtower.

MID-CREDITS: Red Guardian at the supermarket spots a box of Wheaties featuring the team (he had earlier claimed being featured on a cereal box is one of the greatest honors a hero can receive) and badgers an old lady into buying it.

POST-CREDITS: 14 months later, the team jokes about how Captain America/Sam Wilson is assembling his own Avengers and suing them for copyright infringement. They brainstorm some new names (Red Guardian pushes for “New Avengerz”) and discuss how Bob can’t use his powers so he doesn’t awaken the Void (he does the dishes, though). Yelena reports strange space activity and they see the Fantastic Four’s spaceship (with a huge “4” on the side) entering Earth’s atmosphere.

At the base, Ghost immediately headshots Taskmaster and loots her gear.

How the fuck did a serum put the Dark Dimension in Bob's brain?

So is it good

No.

Yes.

MCU Bob is basically male Jean Grey, telekinesis so hax he can basically reshape matter at will.

I get the comparison but how did those powers even come into existence for Bob/Sentry from a vial of liquid?

Val convinces Bob to become the Sentry by acting motherly and claiming she can make him the world’s most beloved superhero.

That's the Boys season 1.