Debra Morgan died in 2013 in the original Dexter series. Her death occurs in “Remember the Monsters?”, the eighth season’s finale, which originally aired on September 22, 2013.
Debra is shot in the abdomen by Oliver Saxon, the serial killer known as the Brain Surgeon. Although she initially reaches the hospital and appears likely to recover, a blood clot during surgery causes a massive stroke. The injury leaves her in a persistent vegetative state.
Dexter kills Saxon and then returns to the hospital, which is being evacuated because of a hurricane. Believing that Debra would not want to remain alive in that condition, he disconnects her life support. He carries her body to his boat and buries her at sea before apparently dying in the storm himself.
A common mix-up is confusing the year of Debra’s death with the year Dexter: New Blood premiered. New Blood began in 2021 and takes place roughly a decade after the original finale. Debra also appears in that sequel as an imagined presence in Dexter’s mind, but that does not change the established year of her death.