The film begins in the midst of World War II, set in a fictional Belgian town called Marwen. Captain Hogie, portrayed by Steve Carell, finds himself battling German soldiers from the skies, but his plane is soon shot down, prompting a crash landing. In the aftermath, he faces a fiery emergency, resulting in the destruction of his shoes. Amidst the chaos, Hogie stumbles upon a briefcase containing women's clothing, and he becomes particularly fond of a pair of high heels, which he decides to wear. His eccentric choice attracts the attention of a group of Nazi soldiers who mock him fiercely. With a defiant spirit, Hogie retaliates by striking the Nazi captain in the groin, but he is quickly overpowered and beaten. Just as it seems all hope is lost, a group of armed women bursts onto the scene, taking out the Nazis and saving Hogie.
Among these women is Wendy, a character represented by [Stefanie Von Pfetten]. In a parallel storyline, we see that Hogie's creator, Mark Hogancamp, is in pursuit of capturing this very moment through photography but is interrupted by a truck, ruining his shot. Mark meticulously organizes the dolls in his own collection, which include one of Deja Thoris, played by [Diane Kruger], symbolizing his struggles with addiction.
As Nicol, as portrayed by [Leslie Mann], moves into a house nearby, Mark grapples with his traumatic past, which includes a brutal attack from neo-Nazis for expressing his affinity for women's shoes. His caretaker, Anna, played by [Gwendoline Christie], visits him monthly, aware that one of Mark's dolls is modeled after her. Through scrapbooks and photographs, Mark attempts to piece together memories from his life before the tragedy. He reminisces about a previous marriage to a real Wendy, and reveals a past filled with both joy and hardship, including time spent in rehab with GI Julie, represented by [Janelle Monáe].
In the crafted world of Marwen, Hogie encounters a milkmaid named Elsa ([Siobhan Williams]), whom he tries to protect. Unfortunately, their budding connection is short-lived as Elsa meets a tragic end at the hands of Nazis, triggering a fierce retaliation from the other women. Deja's magical presence complicates matters, as she eliminates Elsa's existence, much to the horror of her allies.
Meanwhile, Mark must confront his inner demons as he is contacted by his lawyer about the impending sentencing of his attackers, filling him with dread. After a brief trip to a bar where he sparks a conversation with Carlala, played by [Eiza González], about a former waitress, he learns that Wendy has left for California. A subsequent visit to a doll store introduces him to Roberta, who invites him to dinner, highlighting Mark's struggle to engage socially. When he becomes unsettled by the sight of a Nazi doll, he hastily leaves, only to confront further anxiety triggered by a television report concerning his attack.
Nicol's growing friendship with Mark develops into romance, paralleled by their Marwen counterparts. However, the relationship faces trials as Mark grapples with insecurities and the ramifications of his past. During a heartfelt moment, he attempts to propose using a significant Purple Heart medal, but Nicol gently clarifies that she sees him as just a friend, prompting Mark to walk away hurt.
As Mark's mental health deteriorates, thoughts of suicide loom large, reflected in the peril faced by Nicol in the Marwen narrative. A fierce battle ensues against the Nazis, with Hogie’s confrontation revealing Deja's true allegiances as a spy. Their tumultuous showdown results in Hogie's liberation from her spell, bringing a resolution to the siege.
Later, with the support of his friends, Mark bravely faces his attackers in court, delivering a powerful statement that emphasizes his resilience and the healing power of art and friendship—even moving some of his assailants to tears. The film concludes with Mark's evolution as he attends a photography exhibit of Marwencol, a tribute to Nicol. The closing moments portray Mark happily walking home, high heels adorning his feet, carrying his beloved dolls, symbolizing his journey of self-acceptance. A final text reveals that Mark continues to thrive in upstate New York, expanding the captivating world of Marwencol, all captured in a heartwarming photograph alongside his own Captain Hogie.
