Maggie Evans was a young woman who came from Boston to work for Roger Collins in Collinsport, Maine. Roger hired her to work as a governess, tutoring his troublesome son, David. Roger felt that Maggie was a competent instructor, but found her ability to manage David's prankish behavior to be woefully inadequate. He partially expected Maggie to act as a surrogate mother for him. Maggie's presence at Collinwood allowed Roger the ability to ignore his son even more so than usual.
While working for the Collins family, Maggie met and began dating a local artist named Jeff Clark. She often spent her free evenings over at his small art studio.
In June of 1970, David decided to play a trick on Maggie. He pretended to hang himself from the closet in his bedroom. Maggie found him and shrieked in terror. David let himself down and ran out of the house. Roger ordered Maggie to find the boy, and she first began searching around the Collinwood horse stables. Finding nothing but a drunken handyman named Willie Loomis, she extended her search to the original mansion site known as the Old House. David tricked her into following him into a dark room. As she entered, he locked the door behind her and raced back to Collinwood. Maggie was horrified to be stuck inside the damp room. Her terror was heightened when the vampire, Barnabas Collins entered the Old House and attempted to gain access to the room. Fortunately for Maggie, Jeff Clark and a man named Todd Blake arrived and Barnabas was forced to flee before anyone could catch sight of him.
When Maggie returned to Collinwood, she had decided that she had had enough of this miserable job. She gave Mrs. Stoddard her notice, and told her that she would remain until the end of the month.
Later, she went to Jeff's art studio to tell him that she would soon be returning to Boston. Jeff tried to talk her out of it, but a woman named Nancy Hodiak interrupted their discussion when she arrived to pick up a portrait that Jeff had painted for her. Minutes later, Nancy was attacked and killed on Beach Road, leading away from Jeff's studio. Jeff and Maggie found her body and reported it to the local Sheriff's office.
A few nights later, Maggie attended a costume ball at Collinwood being given in honor of the newest member of the Collins family, Barnabas Collins. The theme of the party required all of the guests to dress in costume indicative of the 18th century. Maggie wore an old wedding dress that once belonged to a woman named Josette DuPres. At the party, Barnabas introduced himself to Maggie and became instantly infatuated with her. He likewise convinced her to stay on as David's governess.
In the 18th century, Barnabas had been in love with Josette and now viewed Maggie to be Josette DuPres reincarnated. He set out to own Maggie Evans – body and soul. As the weeks grew on, Barnabas had entered into a working relationship with Dr. Julia Hoffman. Julia was working on a process to cure Barnabas' vampiric condition. The process showed immediate results and Barnabas was once again allowed to walk freely in the daylight.
With a new lease on life, Barnabas pursued Maggie's affections with even more ardor. He gave her an antique music box that once belonged to Josette. Maggie found herself falling for Barnabas, and her relationship with Jeff Clark began to strain. Julia meanwhile, had likewise fallen in love with Barnabas, and was devastated to discover that his heart belonged solely to Maggie Evans. She sabotaged Barnabas' antiviral injections and as a result, he began to rapidly age until he resembled a hideous old man. With the bloodlust overtaking him, he killed Julia and attacked Maggie, drinking her blood. After some time, Barnabas returned to his normal appearance, but he knew that he had to quickly take Maggie as his bride or all would be lost.
He hypnotized Maggie Evans and dressed her in Josette's wedding gown. He took her to an old chapel monastery on St. Eustace Island, where he prepared to turn her into his immortal vampire bride. Jeff Clark discovered them and managed to save Maggie by shoving a crossbow bolt through Barnabas' back, piercing his heart.
Jeff took Maggie back to Collinwood. He asked her if she had ever been in love with Barnabas Collins, to which Maggie responded, "No." Jeff and Maggie's relationship became even stronger after this event.
- The greater portion of Maggie's story is taken directly from a plotline in the original Dark Shadows series, which ran from episodes 225/226 to episode 265 – the long-term repercussions of which, extended even beyond that.
- In the television series, Victoria Winters was David's governess during the early Barnabas Collins storyline, and not Maggie Evans. By the time of the filming of House of Dark Shadows, Alexandra Moltke had left the series and Maggie Evans had been hired as David's governess in the story. The script for the film reflected the then-current cast situation on the series.