The film consists of four "chapters", each related to the other in some or the other way. The film has a unique plot which talks about people who unknowingly ends up helping each other, in a series of events which take place precisely in two days and a night.

The story revolves around five people who are enjoying their life in Kochi. Indrajith Sukumaran plays a creative ad director; Remya Nambeesan as Veena plays a trained dancer; Nivin Pauly plays a waiter at a cafe; Prathap Pothen plays a psychologist; and Lena Abhilash plays the head of a corporation.

Unable to distinguish between his dreams and reality, Roy finds it difficult to maintain any sort of relationship with anyone except his wife Teena, who accepts and loves him wholeheartedly. When Teena, following clues from her husband's dreams, goes missing while searching for a veteran writer, it is up to Roy to find his wife and get her to safety.

Y? (2017) is a suspenseful thriller that revolves around the mysterious kidnapping of a character with a one-letter title. The plot takes unexpected turns, keeping the audience on the edge of their seats.