Percy Jackson series author Rick Riordan plans to work on a new series inspired by Norse mythology, but his fans will have to wait for the series.

According to Courier Press, Riordan will be spending next year working exclusively on book four of The Heroes of Olympus series. The third installment, The Mark of Athena, will be released in October. Here’s more from the article:

Writing about Norse mythology “represents a return to my roots as a reader,” he added, noting that his eighth-grade teacher got him interested in mythology by pointing out that the “Lord of the Rings” books — Riordan’s favorites at the time — were based on Norse mythology.”

On May 1st, Disney/Hyperion released the final volume in The Kane Chronicles which wraps up his Egyptian-mythology project.

As we reported, Riordan also has a short story collection in the works. The stories featured in The Demigod Diaries will be set in the Percy Jackson universe. The title is set for publication on August 14th.