Percy Jackson: The Titan's Curse was a planned third film in the Percy Jackson franchise. 
The plot is unknown, but it may have the same plot as the book, but with some changes in it.
Why It Was Cancelled
- The film was cancelled due to the fact that both Percy Jackson films flopped domestically at the box office.
- The cast members are getting too old to reprise their roles respectively as their characters.
- A reboot is happening that will be more loyal to books accoridng to rumors.