The Assassination of Mar-Vell was an assassination mission executed by Starforce that was aimed at killing Mar-Vell and obtaining the Tesseract-powered Light-Speed Engine. When the engine exploded and Mar-Vell's co-pilot Carol Danvers absorbed the energy from the engine, Yon-Rogg and Minn-Erva took Danvers into their custody.
The incident was covered up by the counter-terrorism intelligence agency S.H.I.E.L.D., who documented it as a failed test flight for Project P.E.G.A.S.U.S., which ended up costing the project at least one billion dollars.
During the Kree-Skrull War, the Kree scientist Mar-Vell was able to develop a Light-Speed Engine by harnessing the energy of the Tesseract, both in her laboratory and in the framework of Project P.E.G.A.S.U.S., which she had infiltrated under the name of Dr. Wendy Lawson. However, despite being a Kree herself, Mar-Vell grew disgusted by the war waged by the Kree Empire, since it was more of a massive colonization which deprived the Skrulls of their own home planet, Skrullos, and all the subsequent shelters they were able to find. Therefore, Mar-Vell switched sides in the war and decided to use her Light-Speed Engine to help the Skrulls reach a place where the Kree would never be able to find them.
Nevertheless, the Supreme Intelligence leading the Kree became aware of Mar-Vell's betrayal, and thus dispatched Starforce members Yon-Rogg and Minn-Erva, with orders of capturing Mar-Vell and seizing her technology so it could be used to further the war effort of the Kree.
Having achieved a first version of her Light-Speed Engine, Mar-Vell, still under the disguise of Wendy Lawson, decided to put it on a trial. Carol Danvers, who worked with her, declared to be ready to perform the test since she had been told that there were lives at stake and that Mar-Vell's technology could help to end wars. Mar-Vell agreed to have Danvers fly an Asis Aircraft equipped with the light-speed engine, and gave her coordinates which were supposed to lead them to Mar-Vell's laboratory.
However, during the flight to space, the Asis aircraft was attacked by the Starforce, causing Mar-Vell to realize that the Kree had come for her and her technology. Ordered by Mar-Vell to do her best to escape from their attackers, Danvers accelerated and managed to get her aircraft behind the Starforce's. She prepared to fire, but the Starforce's ship was able to shoot at them from the rear, and Danvers could not avoid all the blasts, causing the Asis aircraft to be damaged.
With the ejection procedures failing, Danvers and Mar-Vell violently crashed in an uninhabited area, and were able to survive thanks to Danvers being able to slightly straighten the aircraft before the crash. Danvers then got out of the plane and helped Mar-Vell out, noticing her blue blood. As Mar-Vell explained that they had to destroy the engine, she revealed her real name to Danvers. She attempted to shoot at the engine, but she was shot and killed by Yon-Rogg, who then confronted Danvers.
Yon-Rogg explained that harming Danvers was not part of his plan, Danvers angrily stated that there were pararescue on the way. Upon hearing this, Yon-Rogg threatened to kill her, but Danvers pointed him out the light-speed engine he was looking for. However, she immediately shot it, causing it to be destroyed. This unleashed a massive outburst of Tesseract energy which was absorbed by Danvers, leaving her unconscious. After the blast, Minn-Erva noticed that Danvers was still moving, but Yon-Rogg refused to have her killed and instead decided to take her to Hala.
Since Carol Danvers had absorbed the powers of the Tesseract upon the destruction of the Light-Speed Engine, Starforce commander Yon-Rogg decided to bring her back to Hala while she was still unconscious. Now called Vers, she had all her memories of her old life on Earth suppressed, as the Kree made her believe that she was one of their own and that she had lost her memories due to being attacked by Skrulls. Vers was given a blood transfusion by Yon-Rogg, and the Supreme Intelligence had a Photon Inhibitor implanted on her neck to suppress most of her powers while making Vers believe that it was for her own enhancement.
Vers would still have flashes of her old life, especially in her dreams, when she relived the modified memories of the attack. When communing with the Supreme Intelligence, Vers saw it as Mar-Vell, although she did not recognize her as such and had simply forgotten who she was.
The authorities, S.H.I.E.L.D. in particular, covered up the incident and officially stated that Wendy Lawson had died in a plane crash accident during an unsanctioned test flight, which cost Project P.E.G.A.S.U.S. a billion dollars. The project ended soon after since the Tesseract, which was secretly kept in Mar-Vell's Laboratory cloaked in orbit, was nowhere to be found; and Danvers' friend Maria Rambeau was told that the plane's black box could not be retrieved, as they believed it was destroyed in the crash.
Because of Mar-Vell's death, the Skrulls lost the one person who could have helped them to escape from the Kree Empire. They remained scattered across the galaxy, with a group of refugees including Soren and her daughter seeking shelter in Mar-Vell's laboratory, not contacting anyone, especially Soren's husband Talos, out of fear that the Kree would find them.
It was only six years later, while Talos had found Vers and helped her get her memories back, that the Skrulls were finally able to access the light-speed technology. Despite having learned the truth behind Mar-Vell's death and her own origins, Danvers did not exact revenge on Yon-Rogg for having killed her mentor, and instead sent him back to Hala with a warning to the Supreme Intelligence.