Netflix’s Sleeper Mystery Is Rocketing Up the Charts and Leaving Rivals in the Dust

Netflix snuck out a Spanish thriller last week that went from under-the-radar to buzzing fast. It is called The Crystal Cuckoo, it is creepy in a very specific way, and it just muscled into the streamer’s global charts.

Fast facts

• Premiere: November 14, 2025 on Netflix
• Format: Limited series, 6 episodes
• Source material: Based on Javier Castillo’s novel 'El cuco de cristal'
• Directors: Laura Alvea and Juan Miguel del Castillo
• Writers: Jesús Mesas Silva and Javier Andrés Roig
• Producer: Atípica Films
• Cast: Catalina Sopelana leads as Clara, with Álex García, Itziar Ituño, Iván Massagué, Tomás del Estal, and more
• Where it is streaming: Netflix worldwide

So how big did it get this fast?

As of November 18, 2025, The Crystal Cuckoo hit the number 6 spot on Netflix’s global Top 10 (per FlixPatrol tracking). It is charting across a long list of countries, including Argentina, Austria, Belgium, Italy, Mexico, Egypt, and plenty more. It even grabbed the top slot in the Czech Republic, Slovakia, and Spain. For a brand-new Spanish-language title, that puts it firmly among Netflix’s most-watched non-English shows right now, with a decent shot at building for a couple more weeks if word of mouth holds.

What it is actually about

The hook is disarmingly simple: Clara Merlo, a first-year medical resident, collapses from a massive heart attack. She survives because someone else’s heart does not. When she wakes up, the need to know who her donor was turns into an obsession, so she heads to his hometown to get answers.

Here is where it gets twisty: the town is a quiet mountain village that has been living under a cloud of strange tragedies for years. As Clara digs, it becomes clear her donor’s death is not a neat, tragic accident. The series runs on a two-track structure: present day, where Clara arrives and almost immediately gets pulled into a fresh missing-baby case, and the early 2000s, which follows a man named Miguel Ferrer and the incidents that set the whole chain of events in motion. The timelines feed each other in a way that keeps reshaping what Clara thinks she knows.

Why it works

Six episodes is a tight runway for a mystery, and the show uses it well: spare, moody mountain setting; an investigation that starts small and keeps widening; and a central question that is both personal and unnerving. The transplant angle gives the thriller bones, but the story is really about the people orbiting that heart and the community holding a lot of secrets.

The Crystal Cuckoo is streaming now on Netflix.