At the D23 Disney Fan Expo, Walt Disney Studios unveiled the logo/title for the fourth film in the Pirates of the Caribbean series: Pirates of the Caribbean: On Stranger Tides. No plot details have been revealed. What might “On Stranger Tides” mean?

Johnny Depp, who was on hand for the annoucnement, will reprise his role as Captain Jack Sparrow. Erik Davis has noticed that a pirate novel with the title “On Stranger Tides” exists, although it is unknown if it is related to the new Disney film. Here is the synopsis from the novel:

Puppeteer John Chandagnac, bound for Jamaica to recover stolen money from his uncle, becomes Jack Shandy after pirates attack his ship and force him to join their crew. Shandy’s struggle to accept his new life grounds the story for readers, even as Blackbeard and vodun magicians whisk everyone away to dreamlike lands where the Fountain of Youth itself awaits. The chaotic sea battles sing, though at times key events happen so quickly that they get lost in the shuffle as Jack tries to comprehend where he’s going and what’s at stake.

Most people expect the fourth film to follow Sparrow’s adventure to find the Fountain of Youth, a treasure revealed at the conclusion of the third film.

The fourth installment of the Pirates of the Caribbean franchise is gearing up to begin shooting around April or May 2010 for a tenative Summer 2011 release. Disney has previously said that the plan is for Pirates 4 to “hopefully be the first of another trilogy,” which would be shot by itself, and not back-to-back like the previous Pirates sequels. No word on who will direct the new film. Series helmer Gore Verbinski was originally attached to another Pirates film, but left to direct a big screen adaptation of the video game Bioshock. But as you probably know by now, Bioshock got passed to another filmmaker.