Synopsis / Summary / Plot
The Grootfall asteroids transformed the Manifold Territories, actually the ancestral home of Groot's species the Flora Colossi, into Grootspace. Everyone within died but the core Guardians Of The Galaxy were resurrected with Groot to oversee the reseeding of the worlds and the rebirth of everyone else. However Star-Lord's sister Empress Victoria of Spartax is leading an armada to destroy them all.
Nebula and Rocket Raccoon are working on necessary machinery while Drax the Destroyer contemplates the infinite. But Gamora is faced with a large array of bottles of booze. Mantis, this time dressed in cowboy fashion, comments that when Groot assimilated and rebirthed them he saved what they each needed, like tools and machinery for N & RR and the alcohol for G. She shows her the stash of mysterium that they acquired in #2 and claims that it has been preserved for Drax. She also claims that Drax is only pretending to have achieved contentment - he really needs to regain his soul currently trapped in the Soul Stone. As Gamora once had power over the Stone maybe she'd like to join her in a trip to Earth to retrieve D's soul from it. When Mantis tells her that they'll sneak out without telling their leader Peter Quinn, Gamora's all for it. And we see them leaving the Guardian's spaceship that is now Groot in a detached bit of him. And Groot has to explain to Star-Lord what's happened.
The duo land in the middle of the US Southwestern desert, and Gamora is now also suitably cowboy attired. Mantis explains that the Soul Stone is now in the possession of a boy robot named Multitude (see Avengers (2018) Annual), and he's somewhere round here but she's only got some strange hints as to where. So they head into a conveniently local bar, and after a good time (which strangely doesn't involve Gamora having a drink or a fight) leave with directions and the keys to 1 of the many motorcycles parked outside.
On the way Mantis explains how she became her current multi-personality self. She begins with how as the Celestial Madonna she had a son Sequoia who was a plant/animal hybrid who was supposed to be the Celestial Messiah. But he grew up wrong and led plants into a war against animals (see the Empyre event). After that she was lost until she saw an exhibit in the Collector's collection and stole it. It was a sentient garment that she calls Dress which reads her mind and changes her attire and personality to fit her needs. In fact she describes it as becoming her selves from alternate universes.
They arrive at an area in the desert where sculptures of salvaged metal have been erected, and they and the surrounding rock daubed with multi-coloured paint (as per a vision Mantis had). She tries to persuade the android to let them borrow the Soul Stone to help their friend Drax, but the Stone doesn't trust them and prepares to fight. So Mantis morphs to a warrior version and Gamora draws her swords. Multitude employs the souls (or at least the fragments thereof) within the Stone. 1st he sends Adam Warlock against them. Gamora urges Mantis to use the mysterium to absorb the Stone's energy, but she says she has a different plan for it. The boy confronts Gamora with a version of herself. Silver Surfer and Thanos are next, quickly followed by many Earth heroes. But Mantis cycles through many of her selves to defeat them.
Until eventually the soul of Arthur Douglas, saxophone in hand, emerges and tells Multitude to stop because it's him they want. And he wants to be reunited with Drax. So the robot boy allows the soul to pass into Gamora's hands. In return Mantis gives him some advice. He's been trying to find himself, work out his place in the world. She strongly advises meditation rather than relying on an Infinity Stone. And she gives him the mysterium which is worth a lot of money. Gamora objects that they risked a lot to get that, but Mantis says they never actually had any use for it. And they leave.
They return to the Grootship where Gamora throws out all her bottles of booze (and presumably they give Drax his soul). But behind them the Spartoi fleet turns up.