Stan Lee. Jack Kirby. Bob Kane. The legendary creators of Spider-Man, Captain America and Batman have their names written in history. Wonder Woman creator William Moulton Marston, on the other hand, is shrouded in mystery — but “Professor Marston and the Wonder Women” seeks to change that.

The film by “The L Word” veteran Angela Robinson tells the story of Marston (Luke Evans) and the two women who inspired him to create the greatest female superhero of all time.

Initially, Marston was a Harvard psychology professor, assisted by his wife Elizabeth (Rebecca Hall). Together, they studied the human mind and its ability to tell lies. Their teaching assistant, the beautiful Olive Byrne (Bella Heathcote), helps the two with their research and instruction and initially has some awkward sexual tension with Marston.

The three of them go on to invent the lie detector machine using breakthroughs in biology and their studied fields. Late nights of testing one another’s honesty creates an intense bond between the three, heightening the tension between them. The open-minded Marston couple welcomes Byrne into their marriage, and all fall in love with one another. Handled with any less sensitivity and tenderness, “Professor Marston and the Wonder Women” would slip into sexual fantasy, but the film crafts an earnest, loving relationship that just happens to include three people.

This earlier segment of the film includes some clunky references to the character Marston would go on to create, including a lie detector test that wraps around one’s body exactly like Wonder Woman’s lasso of truth and even silver bracelets that Olive always wears.

The three eventually get into BDSM, initially as a test of Marston’s DISC theory, the idea that all relationships begin with either domination, inducement, submission or compliance. It all takes off from there, and climaxes in a beautiful scene that features Olive trying on a burlesque outfit that is nearly identical to Wonder Woman’s costume.

While an awesome scene, this moment is a jarring reminder to the viewer — this is not just a drama about a kinky polyamorous relationship, it’s about the creator of Wonder Woman. It takes a hard turn into focusing on Marston’s creation of the character, and how he was influenced by many small details of his psychological studies and his relationship with Elizabeth and Olive.

When “Professor Marston and the Wonder Women” focuses on a loving romantic relationship between three people, it’s an amazing, groundbreaking film. But when it’s actually about Wonder Woman, the film hits the brakes and tells a story it seems like Robinson feels obligated to tell, rather than something she wants to tell.

Crafting a believable, emotional and highly sexual relationship between three individuals is a nearly impossible task, and on that front, the movie miraculously succeeds. It is only when the film cares more about comic books that it suffers and falls into the arena of conventional historical biopics.

“Professor Marston and the Wonder Women”

Rating: R

Runtime: 120 minutes

Score: 3.5/5 stars