Which 2016 Spanish mystery thriller film, directed by Oriol Paulo, centers on businessman Adrián Doria, who is accused of murdering his lover and must work with a prestigious lawyer to construct a defense?

The film you're thinking of is "The Invisible Guest (Review)," originally titled "Contratiempo" in Spanish, which translates to "Setback." This gripping 2016 mystery thriller was indeed directed by Oriol Paulo, known for his intricate plots and surprising twists. The story centers on Adrián Doria, a successful businessman who finds himself in a locked hotel room with his murdered lover, Laura Vidal, and is subsequently arrested.

Desperate to prove his innocence and construct a solid defense, Adrián enlists the help of Virginia Goodman, a renowned and sharp defense attorney with an impeccable record. Over the course of a single evening, they intensely dissect the events leading up to Laura's death, with Adrián recounting his version of the truth through a series of flashbacks. However, Goodman, with her keen eye for detail and relentless questioning, pushes Adrián to reveal deeper layers of the story, exposing inconsistencies and hidden motives.

"The Invisible Guest" is celebrated for its masterful storytelling, which keeps audiences on the edge of their seats, constantly re-evaluating what they believe to be true. The film's narrative is a clever tapestry of unreliable accounts and shocking revelations, culminating in a truly unexpected ending that has earned it significant international acclaim, particularly in markets like China where it was a major box office success. Its popularity has even led to several international remakes in various languages, a testament to its compelling and suspenseful plot.