Diane Morris was the villainess of "Silent Night 2", the 5th Super Chiller of R.L. Stine's original Fear Street series (published on December 1, 1993). She was a recent graduate of Waynesbridge High by the events of the book and was the girlfriend of unemployed high school dropout Paul "Pres" Nichols (giving him the nickname Pres for his resemblance to Elvis). The couple was poor and lived in Pres's shoddy apartment, with Paul having recently been fired from the Dalby Department Store for stealing. Desperate for easy cash, Diane and Paul made a plan: they would kidnap Reva Dalby, the spoiled daughter of Mr. Dalby, and hold her for ransom. Diane showed giddy joy for their plot, believing it would work out "just like in the movies".
After Pres and Diane's first attempt to abduct Reva failed, the pair enlisted the help of Pres's brother Danny to kidnap Reva from the department store (where she worked). The plan went through without fail, despite Diane having to move her car at the behest of a guard. But it was later revealed that Diane and Danny (Pres having been arrested and unable to assist in the kidnapping) had really abducted Reva's cousin Pam instead of Reva. A few days after releasing Pam at Reva's house, Diane and her two cohorts recapture her along with Reva, having enlisted Pam's help in luring Reva to her house under the false promise of releasing her once they had Reva.
After taking the girls to Dalby's and tying them to chairs on the fifth floor, Diane went to find a payphone to call Mr. Dalby with ransom demands, completely uncaring to how violent Danny was becoming with Reva and Pam. Reva was able to free herself and Pam and they ran to escape, with their three kidnappers in pursuit. An FBI agent who had been following Reva arrived and went to apprehend Pres and Diane, and Danny attempted to recapture Reva and Pam again. But when Reva fought back and the girls were able to disarm him, Danny tried to run and was killed when he tried to use a broken elevator, sending him falling to his demise. Pres and Diane were later handcuffed and arrested.