Medium Episode 6.20 Time Keeps on Slipping

Allison dreams Ariel has turned into an old woman. She finds Ariel's up late studying for her AP Chemistry class. The next day when she turns in her exam, she has a vision of her teacher, Mrs. Kerrigan, standing and crying over a baby, Brendan. An exhausted Ariel is supposed to babysit Brendan that night, so her friend Liam urges her to nap in his car. Ariel wakes up in the car, not remembering how she got there, as if she's flashing forward in time. She jumps in time again to later that night babysitting Brendan and finds Mrs. Kerrigan shot to death in the hallway. And then jumps forward again to later that night. Another jump, this time 10 years in the future, she's married to Liam and has a 5 yr. old, Anna. Now living 10 years in the future, Ariel dreams of Mrs. Kerrigan begging the killer to think of their son, so police question Mr. Kerrigan, who pleads innocence. Allison figures out what's going on and tells Ariel to come over, but before Ariel learns the truth she flashes to find herself standing at her mother's grave years later. Ariel notices Brendan, now a teenager, looks just like Liam. Ariel has a vision of Liam shooting Mrs. Kerrigan. Liam confesses he was worried about college and his future, so he killed Mrs. Kerrigan and Allison before Ariel learned the truth. When he shoots Ariel, she wakes up back in the present day and stops Mrs. Kerrigan's murder.