Derek begins a critical clinical trial to find a cure for Alzheimer’s, driven by his fear that Meredith will inherit her mother's condition. However, the season finale is defined by Meredith’s choice to tamper with the trial to ensure Adele Webber receives the active drug, a decision that threatens her marriage and career. Key Plot Points & Conflicts

The season opens one month after the shooting, with the doctors struggling to return to their routines. Derek Shepherd seeks adrenaline through high-speed driving, while Cristina Yang suffers from severe PTSD, ultimately leading her to quit surgery for a time and even take up bartending. A standout "documentary-style" episode, "These Arms of Mine," captures this recovery process six months later, as a film crew visits the hospital to witness the survivors' progress. Major Character Milestones

This season is marked by significant life changes for the core cast, including several "firsts" for the series: