Despite helping win the war, defeating Ares and still loving humanity, Diana is still left sobered, emotionally broken, psychologically scarred, and devastated over not having been able to save the Belgian village from Dr. Poison, as well as over her beloved Steve Trevor's self-sacrificing death. Indeed, Diana would later claim that she "would never be the same" ever again after World War I. Moreover, in the years that followed, Diana bore witness to a "century of horrors" (Wars, Fascism, Communism, nuclear weapons' deployment, geopolitical brinkmanship, racism, homophobia, genocides, war crimes, propaganda, and etc.), and due to all of this occurring without Ares being there to spread corruption, Diana almost completely lost faith in humanity, coming to believe that humans "made a world where standing together is impossible". As such, Diana resolved to mostly abandon superheroism for 100 years.
Siracca tells Diana how she and her mother were killed by the hands of the jealous goddess Hera. Although she was torn to shreds by Hera's fury, Zeus took pity on her and turned her into wind. The very same wind that spills secrets to Lennox. Wonder Woman share her encounter with Hera and how she so desperately needs to find Zola's child, stolen due to Hermes. Siracca attempts to help Diana in finding Hermes and the baby. She suggests meeting Milan, once again, another child of Zeus for advice. Diana treks off to New York to find him.
Additional music featured in the film are: "Another Little Drink Wouldn't Do Us Any Harm" by Clifford Grey and Nat Ayer and performed by Edgar Trevor and Cecil Cooper; "Molly O'Morgan" written by Fred Godfrey and Will Letters and performed by Ella Retford; "It's a Long Way to Tipperary" written by Jack Judge and Harry Williams; "Sous les ponts de Paris" written by Jean Rodor and Vincent Scotto and performed by Lucienne Delyle; "I'll Walk Beside You" written by Edward Lockton and Alan Murray and performed by Ewen Bremner; "Green Grow the Rushes, O" written by Robert Burns and performed by Ewen Bremner; and "Schatzwalzer Op. 4" written by Johann Strauss II and performed by the Berlin String Quartet.
After a training session, Diana happened to come across Captain Steve Trevor during his escape from the Imperial German Army. A battle soon followed, as the Germans tracked Trevor to Themyscira, where they invaded in pursuit of Doctor Poison's notes. The loss of her aunt and realization of Mankind's downfall during the absence of the amazons convinced Diana to join the war effort, recognizing Ares as the instigator of the conflict.
The final remaining relics Darkseid needed were being guarded by A.R.G.U.S. at their HQ, so Darkseid decided to use a Boom Tube to transport the building and all its contents to his base in the Amazon Rainforest. The Female Furies retrieved the relics and put them into place while Wonder Woman fought Darkseid. With the relics' power, Darkseid was able to open a portal to Themyscira. As it is impossible for one who has set foot on Themyscira to return after leaving, Diana was unable to follow Grail through the portal. Grail invaded and began transforming the Amazons into creatures resembling Darkseid's Parademons. As Jason had never actually set foot on Themyscira, he followed Grail and met his mother Hippolyta for the first time since his birth. While Jason and Hippolyta fought off the transformed Amazons, Wonder Woman was able to defeat Darkseid through her love for her deceased father, Zeus, and her half-siblings, calling their spirits out of Darkseid's body and destroying him from the inside. The Amazons captured Grail and imprisoned her in the prison beneath Themyscira, alongside Ares, while Darkseid re-emerged somewhere on Earth. Jason was gifted a magical spear from his mother and returned to Earth.
A day before Whedon's departure from Wonder Woman, Warner Bros. and Silver Pictures purchased a spec script for the film written by Matthew Jennison and Brent Strickland. Set during World War II, the script impressed executives at Silver Pictures. However, Silver stated that he had purchased the script because he did not want the rights reverting; while stating the script had good ideas, Silver did not want the film to be a period piece. By April 2008, Silver hired Jennison and Strickland to write a new script set in contemporary times that would not depict Wonder Woman's origin, but explore Paradise Island's history.
^ Sanderson, Peter (September–October 1981). "Thomas/Colan Premiere Wonder Woman's New Look". Comics Feature. New Media Publishing (12/13): 23. The hotly-debated new Wonder Woman uniform will be bestowed on the Amazon Princess in her first adventure written and drawn by her new creative team: Roy Thomas and Gene Colan...This story will appear as an insert in DC Comics Presents #41.