"Wrath of the Titans" is the Olympian peak of Hollywood creative bankruptcy, a sequel to a remake of a movie that wasn't that good to begin with executed as a special-effects demo reel in the place of actual entertainment.
Starting a few years after "Clash of the Titans" left off, the demigod Perseus (Sam Worthington) is now a single dad raising his son Helius (John Bell) as a peace-loving fisherman. Then chaos erupts from the Underworld, where Hades (Ralph Fiennes) has trapped his brother Zeus (Liam Neeson) Perseus' father to release their father, Kronos, from his eternal prison, which would precipitate the end of the universe or something.
So Perseus must partner with the warrior queen Andromeda (Rosamund Pike), find Poseidon's demigod son Agenor (Toby Kebbell), who will lead them to the god Hephaestus (Bill Nighy), to find a way into Hades and give Perseus a weapon with which he can stop Kronos and defeat his half-brother, the war god Ares (Edgar Ramirez), who's mad at Zeus for favoring Perseus over him. (The script's Oedipal undertone is the most Greek thing about this movie.)