Years later, the Guardians received a distress call, discovering the Asgardian Thor amongst the wreckage of a ship. Thor informed the Guardians that Thanos now had acquired two of the six Infinity Stones. Afraid, Gamora warned them that if Thanos got ahold of all six stones, he would be able to destroy the universe with a snap of his fingers. Gamora, Quill, Drax and Mantis traveled to Knowhere to attempt to stop Thanos from getting the Reality Stone from the Collector. During their journey, Gamora made Quill promise to kill her should Thanos get ahold of her, saying she had information which he could use to destroy the entire universe.
On Knowhere, seemingly finding him before he had the Reality Stone, Gamora fatally stabbed Thanos. When he fell to the ground, asking her why she had done it, she broke down in tears. Thanos revealed he already had the Reality Stone and his “death” was a ruse, noting her reaction had proven she still cared for him. Thanos grabbed Gamora and while Peter initially resisted her pleas to shoot him, he finally went through with his promise to her, wanting to give her agency. However, Thanos used the Reality Stone to turn his blast into mere bubbles, as he teleported away with Gamora.
On his ship, Thanos showed Gamora that he had captured Nebula when she had attempted to kill him. He tortured her in front of Gamora, until Gamora revealed the information she had kept from him—that she knew that the Soul Stone was located on the planet Vormir.