Ideas can be too easy, if they remain in the realm of unrealised abstraction. Like a secret, I’d always nurtured the idea of making a Professor Shonku film. Just like the detective Feluda, the scientist invented by my father Satyajit Ray for his sci-fi stories has intrigued me for decades. Bengali readers, with their penchant for tales of quirky intellectuals, loved the Professor Shonku stories. But he still exists as a mental artefact—each reader has conjured up his or her own Professor Shonku. Do these diverse impressions have something in common that a director can tap? Feluda has been played by different actors—all of them have instantiated, embodied, extended or even challenged everyone’s imagined Feluda. That fascinating, complex play has been denied to Prof Shonku. So I wanted to put a cinematic face to Professor Trilokeshwar Shonku.