For the casual London-courtroom rubbernecker, 2020 has been a doozy of a season. Johnny Depp and Amber Heard’s booze-filled “Disco Bloodbath”; the High Court teaser trailer for Meghan and Harry vs. the World. And now the series grand finale—a high-stakes, big-budget, multi-continent family drama that’s been four long years in the making. They haven’t skimped on the pyrotechnics.

The story begins in 2016, when a High Court judge in London awarded Ms. Tatiana Akhmedova a $600 million settlement in her divorce from Farkhad Akhmedov—a Putin ally and oil-and-gas baron—in what was soon billed as one of the most expensive splits in history. Lawyers for Mr. Akhmedov, however, immediately condemned the ruling—and have since done everything in their power to keep Ms. Akhmedova away from her ex-husband’s assets.