In , titled " Love/Addiction " , the staff of Seattle Grace treats victims of a massive apartment explosion that turns out to have been a meth lab. The episode explores the destructive nature of various "addictions," ranging from drugs to complicated romantic entanglements. Key Plot Developments
: Derek Shepherd realizes he is "addicted" to his non-committal relationship with Meredith, which they jokingly refer to as "S&M" (sex and mockery). Watch www xrysois se Greys Anatomy S04E02
: The doctors treat victims of a "stove explosion" that is later revealed to be a meth lab. Alex Karev deals with the fallout when a father endangers his infant son, leading to a physical confrontation and the father briefly fleeing with the child. In , titled " Love/Addiction " , the