Rick Riordan has revealed the cover for his latest crossover short story, “Staff of Serapis,” which features Annabeth Chase and Sadie Kane.

The reveal comes via The Huffington Post, where Riordan showed the cover live on air. You can check it out below, followed by the video.

The release date for the short story is April 8. This is the day The Mark of Athena will be released in its paperback version, and “The Staff of Serapis” will be included in the back of the third Heroes of Olympus novel.

Riordan’s description of the book says, “In this adventure, Annabeth encounters more oddities in the subway than usual, including a two-headed monster and a younger blond girl who reminds her a little of herself….”

“The Staff of Serapis” is a followup short story to “The Son of Sobek,” which was the first crossover short story Riordan wrote. “The Son of Sobek” featured Percy Jackson meeting Carter Kane, Sadie’s brother.

If you can’t wait to read “The Staff of Serapis,” you’re in luck! Riordan has released the first few pages as a teaser.

If you’ve already bought The Mark of Athena and don’t want to buy the paperback just for the short story, don’t worry! “The Staff of Serapis” will be available as an eBook and an audiobook, read by Rick Riordan himself, on May 20.

“The Staff of Serapis” comes in at around 60 pages, which is a little longer than “The Son of Sobek.” Riordan says he enjoyed writing this short story (“Dang, it was fun to write the dialogue between those two!”), and we’re certain we’re going to have just as much fun reading it.

Riordan will also be releasing two additional books this year. The first one is Percy Jackson’s Greek Gods, a book about the Greek myths as told by Percy Jackson himself. That comes out August 19.

The big one, however, is The Blood of Olympus, the fifth and final book in the Heroes of Olympus series. This will come out on October 7.