Much of the discussion surrounding Amazon Prime Video spy series Citadel is about just how gosh darn expensive the whole thing was to make. With a reported production budget of around $300 million, Citadel is one of the most expensive TV series in history, despite its first season featuring only six episodes all well under one hour long.

Even here at your friendly neighborhood Den of Geek, we wondered how a simple spys-to-lovers two-hander could end up with such a hefty price tag. With the conclusion of Citadel season 1’s sixth and final episode of May 26, however, we’re finally starting to get a better idea of where all that money went.

It turns out that Citadel season 1 will be followed up with not only a second season but also Citadel: Diana, the first of what Amazon hopes is surely many spinoffs. Despite what you may have seen on some less enlightened corners of the internet,...