HBO has switched off Westworld.

The network has decided to cancel the sci-fi drama after its recent fourth season.

It’s an unexpected and surprising fate for a series that was once considered one of HBO’s big tentpoles — an acclaimed mystery box drama that racked up 54 Emmy award nominations (including a supporting actress win for Thandiwe Newton).

Last month, co-creator Jonathan Nolan said in an interview that he hoped HBO would give the series a fifth season to wrap up the show’s ambitious story. “We always planned for a fifth and final season,” Nolan said. “We are still in conversations with the network. We very much hope to make them.” Co-creator Lisa Joy likewise reiterated the series has always been working towards a specific ending: “Jonah and I have always had an ending in mind that we hope to reach. We have not quite reached it yet.”

Yet linear ratings for the expensive series fell off sharply for its third season, and then dropped even further for season four. Westworld‘s critic average on Rotten Tomatoes likewise declined from the mid-80s for its first two seasons to the mid-70s for the latter two. Fans regularly griped that the show became increasingly confusing and tangled in its mythology and lacked characters to root for. Warner Bros. Discovery CEO David Zaslav has pledged aggressive cost cutting mandate, though insiders maintain that it was not a factor in this decision.

Still, HBO — and, increasingly, other cable networks and streamers — typically like to give major series creators time to craft an ending for their serialized shows as it keeps its subscribers from getting upset (such as the years-long fandom outrage after Deadwood was axed). Plus, a show that has a beginning, middle and an end arguably increases the perceived value of a streaming and home video product compared to a title that feels unfinished. The fourth season of Westworld wasn’t entirely a cliffhanger, however, and could be said to be rather ambiguous (as discussed in our post-season interview with Joy, where THR associate editor Abbey White pointed out, “It felt like the show could have ended there”).

Here’s HBO’s statement: “Over the past four seasons, Lisa and Jonah have taken viewers on a mind-bending odyssey, raising the bar at every step. We are tremendously grateful to them, along with their immensely talented cast, producers and crew, and all of our partners at Kilter Films, Bad Robot and Warner Bros. Television. It’s been a thrill to join them on this journey.”

Here’s Kilter Films’ statement: “Making Westworld has been one of the highlights of our careers. We are deeply grateful to our extraordinary cast and crew for creating these indelible characters and brilliant worlds. We’ve been privileged to tell these stories about the future of consciousness – both human and beyond – in the brief window of time before our AI overlords forbid us from doing so.” 

More to come…