Plot

Wonder Woman finds herself battling two opponents, Maxwell Lord, a shrewd entrepreneur, and Barbara Minerva, a friend-turned-foe. Meanwhile, she also ends up crossing paths with her love interest.

In 1984, after saving the world in Wonder Woman (2017), the immortal Amazon warrior, Princess Diana of Themyscira, finds herself trying to stay under the radar, working as an archaeologist at the Smithsonian Museum. With the memory of the brave U.S. pilot, Captain Steve Trevor, etched on her mind, Diana Prince becomes embroiled in a sinister conspiracy of global proportions when a transparent, golden-yellow citrine gemstone catches the eye of the power-hungry entrepreneur, Maxwell Lord. Now, as a dear old friend from the past miraculously enters the picture, and Barbara Minerva, Diana's insecure gemologist colleague, gives in to desire, suddenly, deceit, greed, and false promises catapult Maxwell into the limelight. More and more, cataclysmic events push the world to the brink, and emotionally vulnerable Diana must address a cruel dilemma. Can mighty Wonder Woman save humankind once again?—Nick Riganas

It's 1984 and Diana Prince is working at the Smithsonian in Washington. A new shipment of artefacts has come in, one of which is a seemingly innocuous, not-very-valuable stone. However, failed businessman Max Lord recognises the stone as the Dream Stone, a stone that grants wishes, and quickly steals it and starts abusing its powers. This puts the world in jeopardy.—grantss

As a young girl, Diana Prince participates in a multi-stage athletic competition on Themyscira against older Amazons. After falling from her horse and taking a shortcut, she is disqualified. Diana's mother, Queen Hippolyta, and her aunt Antiope lecture her on the importance of truth, because "no hero is born from lies".

In 1984, decades after the events of World War I, Diana works as a senior anthropologist at the Smithsonian Institute in Washington, D.C., specializing in the culture of ancient Mediterranean civilizations. Diana continues to fight crime as Wonder Woman, albeit while maintaining some anonymity. At work, she meets Barbara Ann Minerva, an insecure woman who idolizes and envies Diana for her beauty and confidence and befriends her. After Wonder Woman foils an attempted robbery, the FBI asks Barbara to identify a cache of stolen antiquities from the robbery. One item both women take notice of has an inscription in Latin.

Businessman Maxwell Lord visits the Smithsonian under the guise of making a donation. Secretly, he covets the "Dreamstone," hoping to save his failing oil company. Both Diana and Barbara unknowingly use the stone to fulfill their own desires. Diana wishes for her deceased lover, Steve Trevor, to return, causing his soul to take over another man's body. Barbara wishes to become strong and beautiful like Diana. During a gala night at the Smithsonian, she meets Maxwell, who seduces her in order to gain access to her office so he can take the Dreamstone. He wishes to become the embodiment of the stone and gains its power to grant wishes, while also able to take whatever he desires in return.

Maxwell becomes a powerful and influential figure as his body begins to slowly die, while leaving chaos and destruction in his wake as his wishes trigger instability and conflict. Barbara, Diana and Steve investigate the Dreamstone's powers further and discover that it was created by Dechalafrea Ero - the god of treachery and mischief. The stone grants a user their wish but exacts a toll. The only way to reverse the exchange is by renouncing the wish or destroying the stone itself. Steve realizes that his existence comes at the cost of Diana's power. Both Diana and Barbara are unwilling to renounce their wishes, so they try to find alternative solutions.

Maxwell, upon learning from the President of the United States that the US satellite broadcast system can transmit signals globally, decides to use it to grant wishes to the entire world, inadvertently giving the United States more nuclear weapons which threatens to start a nuclear war with the Soviet Union. Barbara joins forces with Maxwell to prevent Diana from harming him. Steve convinces Diana to let go of him and renounce her wish, regaining her strength. She returns home and dons the armor of the legendary Amazon warrior Asteria, then heads to the broadcast station and battles Barbara, who has been transformed into a being of pure rage after wishing to become an "apex predator". After defeating Barbara, Diana confronts Maxwell and uses her Lasso of Truth to communicate with the world through him, convincing everyone to renounce their wishes. She also shows Maxwell a vision of his son, Alistair, wandering the street as chaos ensues from his fulfillment of everyone's desires. Maxwell renounces his wish and returns home to reunite with his son, averting global thermonuclear war.

Some time later, Diana meets the man whose body Steve was inhabiting, while she continues to protect the world.

Ultimately, Asteria is revealed to be alive and living among humanity in secret, very much like Diana.