I could quit, but here's the thing: I love the playing field.
Meredith Grey woke up next to a guy named Derek. And she promptly said good bye to him, presumably for good, as she went off for her first day of work as a surgical intern at Seattle Grace Hospital. Meredith, along with fellow interns Cristina Yang, Izzie Stevens, and George O'Malley, all get assigned to surgical resident Dr. Miranda Bailey, but they would all come to know her as "The Nazi" (for her abrasive treatment of interns).
Meredith's first patient, a teenage beauty pageant contestant, recently began suffering from seizures so severe they threatened her life. As a neurological disorder that might need surgery, a neurosurgeon new to Seattle Grace gets put on the case to work with Meredith. That neurosurgeon is none other than Dr. Derek Shepherd, Meredith's would be one night stand. Derek wants to talk to Meredith about the previous night, but Meredith wants none of that. He's an attending, she's an intern, that's what their relationship should be.
Meredith forms an immediate bond with Cristina that gets quickly tested when Derek chooses Meredith over Cristina to scrub in on brain surgery (it would've been a first for either of them). Izzie is assigned to do rectal exams amidst frustrating bouts of deciding when it's appropriate or not to bother Bailey. And George gets selected by the arrogant Dr. Preston Burke to actually perform a surgery an honor he allegedly bestows on the intern who shows the most promise, but in actuality is for the intern he just wants to torture and make an example of in front of the others. George freezes up during an appendectomy with Burke and gets branded "007" license to kill by a fellow intern that rubs everyone the wrong way Alex Karev. Alex also insults Meredith, but he gets his comeuppance when she is able to offer a proper diagnosis for one of Alex's patients in front of Dr. Richard Webber, Chief of Surgery at Seattle Grace.
Dr. Webber, by the way, turns out to be a friend of Meredith's mother, the famous Dr. Ellis Grey (whom all the interns hold in the highest regard). We get the impression that the relationship between Meredith and Ellis wasn't the best Ellis didn't think Meredith had what it takes to go to medical school but no one, save for Meredith, knows that early onset Alzheimer's Disease has left her a shell of the person she once was, relegating her now to a nursing home.