With Jon and Sansa defeating Ramsay, Daenerys beginning her journey across the Narrow Sea and Arya returning to Westeros, Game of Thrones’ most recent season seemed to end on an uplifting note. However, George R.R. Martin — who wrote the A Song of Ice and Fire book series that the show is based on — wants fans to know that his upcoming sixth novel may not be as triumphant.

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“There are a lot of dark chapters right now in the book that I’m writing,” he said during a Q&A at the Guadalajara International Book Fair, according to Entertainment Weekly. “It is called The Winds of Winter, and I’ve been telling you for 20 years that winter was coming. Winter is the time when things die, and cold and ice and darkness fill the world, so this is not going to be the happy feel-good that people may be hoping for. Some of the characters [are] in very dark places.”

The author went on to tease the series’ long-awaited conclusion — the seventh and final book, A Dream of Spring — noting that there will be no fairytale ending. “I’m not going to tell you how I’m going to end my book, but I suspect the overall flavor is going to be as much bittersweet as it is happy.”

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Read more at EW.com.