: The season introduces Lexie Grey, Meredith’s eager half-sister, whose presence forces Meredith to confront her complicated family history.
: Meredith, Cristina, Izzie, and Alex transition from interns to first-year residents, each managing their own group of interns. Greys Anatomy - Season 4
: This season was shortened to 17 episodes due to the 2007–08 Writers Guild of America strike, leading to a more episodic feel compared to earlier seasons. Major Plot Arcs Favorite Moments from Grey's Anatomy Season 4 : The season introduces Lexie Grey, Meredith’s eager
marks a major turning point for the staff at Seattle Grace, shifting from the "intern era" to the challenges of residency while introducing new faces that would become series staples. Key Season Overview : The season introduces Lexie Grey