The recent appearance of 'X-Men: Apocalypse' at the San Diego Comic-Con has revealed several great details about the movie. The trailer that was unveiled introduced the Four Horsemen, mutants who have been manipulated by Apocalypse. It also had a clue as to how Professor X finally loses his hair.

It turns out that Bryan Singer hasn't divulged all of the secrets in 'X-Men: Apocalypse.' However, he did post clues on which way the film's storyline will eventually go.

The director has just posted a new picture on Instagram of himself in the middle of rubble. "Tip toeing through ruined #Cairo #1983," he wrote.

The photograph suggests that a scene will be filmed in Cairo. Fans of the X-Men comic books already know that Storm was discovered by Professor X in the said city, where she lived off stealing from people. There is a great possibility that Singer will be introducing Storm's origin story in 'X-Men: Apocalypse.'

Storm, whose real name is Ororo Munroe, is already an established character in the 'X-Men' franchise. The character has been portrayed by Academy Award winner Halle Berry, and will be played by Alexandra Shipp in the new film.

The date indicated in Bryan Singer's Instagram photo explains why Shipp's version of Storm is sporting a Mohawk, since the character underwent a punk stage during the 1980's.

Fans are also speculating that there might also be a backstory for Cyclops, who will be played by Tye Sheridan, and Jean Grey, who is portrayed by 'Game of Thrones' actress Sophie Turner.

'X-Men: Apocalypse' also features returning stars Michael Fassbender, James McAvoy, Rose Byrne, Evan Peters, Jennifer Lawrence and Nicholas Hoult. The new actors include Lana Condor, Kodi McPhee-Smit, Lucas Till, Olivia Munn, Ben Hardy and Oscar Isaac.

Watch out for the mutants when 'X-Men: Apocalypse' hits theaters on May 27, 2016.