In Ancient Greece,Hera,Queen of the Gods,created the Immortal warrior women from her own blood called the Amazons. They fought against the men who are corrupted by Ares,the God of War. After he was defeated,the Gods gave the Amazons an island to live. The Amazon leader,Hippolyta came to Zeus to ask for the island to be hidden. Zeus will grant her wish if Hippolyta lays with him which she does. As the Island is hidden,Hippolyta became Queen to the Amazons of Themyscira & realized that she's pregnant with Zeus. She knew & fear what Hera is capable of,so Hippolyta invents a story about creating a child from clay & Zeus brought it to life.
Centuries ago,A US Navy SEAL,Steve Trevor is shot down during the dogfight & crash-lands in Themyscira. He was captured by the Amazons & was interrogated with the Lasso of Truth. Knowing that Steve is not the enemy,Hippolyta decides that he needs to return home. Despite her words of dangers to the outside world,Hippolyta's daughter,Diana participate in contests of strength,winning the right to bring Steve home.
Later,Diana's Aunt,Astarte,seduced by Ares,kills her sister,Antiope & releases him. Diana takes Steve in her invisible jet. While there,They learned a commotion going on at the city. She spent time with Steve until they're interrupted by Harpies,who are sent by Ares. Diana puts on her armor & her Tiara and fought with them. After she kills the two,Diana interrogates one & learns about Ares' release.
Ares summons his armies to attack the city. Diana & Steve fought against the army with the Amazons' help. Hippolyta defeats Astarte while Diana fights with Ares,who reveals that She is a Demigoddess. He asked her to join him,but Diana refuses & overpowers him. She grabs the sword & decapitates Ares. Steve rush towards Diana & they shared a kiss.
Later,Hippolyta gave Diana a task to protect the outside world where she is dubbed as "Wonder Woman".
Mid-Credits:
The Police investigates the crash site of a Spaceship. A Police Man walks far away from it & secretly shifts into a "Green Martian".
Post-Credits:
In Astarte's cell,She warns Hippolyta that releasing Ares & the attack of United States was just the beginning.