Hayley met Prometheus after she found him in an avalanche on a mountain somewhere in Europe. Since Prometheus didn't know his own name, Hayley gave him the name Shane and the pair ended up sleeping together. During sex, 'Shane' suffered a heart attack and died, due to the fact that he was cursed, and Hayley fled after 'Shane' came back to life.
9 months later, Hayley gave birth to Oliver. When Oliver turned 7, he started dying and coming back to life. She then decided to search for 'Shane'.
Hayley along with her son, Oliver visited Sam and Dean at their hotel. Hayley introduced Oliver and herself and asked for 'Shane' after investigating the 'zombie' reports. She explained her history with Shane to Sam and Dean and how she found him in the midst of an avalanche. After 'Shane' re-animated, Hayley introduced his son Oliver, to him
Later on, Hayley burst into the motel room carrying Oliver, who suffered a nasty fall. 'Shane' deduced that Oliver has inherited his father's curse and after both of them have been taken to the Men of Letters bunker, Sam and Dean explained to her who and what 'Shane' was and what had been happening to Oliver. She was skeptical at first but later was convinced by Prometheus.
After summoning Zeus, the negotiation did not turn out the way they wanted. Hayley, not wanting her son to be cursed anymore, helped Zeus escape by ruining the trap, thinking that he would lift the curse. But Zeus turned the tables on them by using the opportunity to torture Prometheus and kill Oliver to hurt Prometheus even more.
Artemis arrived and wanted to kill her father, as he wasn't the man she once knew. Zeus used Prometheus as a shield to protect himself from Artemis' arrow. Hayley shared a look with Prometheus who then shoved the arrow through himself and into Zeus, killing both with Prometheus dying permanently. However, this broke the curse on Oliver as well. Hayley then helped Dean cremate Prometheus's body.