Sorry it took me so long to respond. Completely forgot about your post. I see some of your questions have already been answered. So, here's what happened: While Master Chief was off at Delta Halo, Blue Team (Fred, Linda, Will) was fighting the Covenant on Earth, going on a multitude of missions to stop Covenant digs and interrupt their operations. During this, Lord Hood received a message from Dr. Halsey (who had kidnapped Kelly prior) stating that there was Forerunner tech at Onyx that could turn the tide of the war, and she needed Spartans to secure it. Blue Team was given the order to get to Onyx. They hijacked a Covenant ship and landed at Onyx. There, they met up with a handful of SPARTAN-IIIs, Kurt, Kelly, Dr. Halsey, and CPO Mendez. In the process of accessing the Shield World at Onyx, many of the SPARTAN-IIIs were killed along with Will and Kurt. The survivors accessed the Shield World and Onyx was destroyed. The surviving Spartans were all designated as Blue Team members. In 2553, ONI located the slipspace bubble containing the Shield World. After conversing with the survivors inside, they were able to bring the Shield World into real space. From there, the survivors were rescued, except Dr. Halsey who was arrested for war crimes. From there, Blue Team from there would be broken up and downsized to just Linda, Kelly, and Fred. From there, Blue Team went on a series of classified missions, rooting out remaining pockets of Covenant Loyalists, and quelling the insurrection. In July 2557, the Master Chief would be asked to advise Blue Team on a mission to investigate the loss of contact with Black Team and the science team on Installation 03. Arriving at Gamma Halo, they would find that the composed souls of New Phoenix's residents had been transported here, and were being sent through a service portal to the Composer's Forge. Arriving there, they would find the Didact, who had begun to amass a multitude of Composers to finish off humanity. The fight with the Didact would be perilous, with the Master Chief suffering considerable damage and injury. The only reason they survived was with the help of 859 Static Carillon. The Master Chief came up with a plan to use the composers against the Didact, and he successfully defeated him. The Didact is currently considered contained. From there, the Master Chief would be reinstated with Blue Team, and would go on a series of, as of yet, classified missions.