Royal delight PBS’s The Lost Prince BY JOYCE MILLMAN

Masterpiece Theatre opens its 34th season with one of the finest, and strangest, skeleton-in-a-royal-closet dramas it has ever offered. The Lost Prince (WGBH, October 17 and 24 at 9 p.m.), a based-in-fact mini-series about a royal family secret in the reign of George V, was the talk of Great Britain when it aired on the BBC earlier this year. It’s not hard to see why. In the aftermath of Hurricane Diana, and faced with such depressing spectacles as Charles and Camilla making like brazen lovebirds and young Harry, the stoner prince, being carried out of his own birthday party in a daze, Britons (and anyone else still fascinated by the train wreck known as the British monarchy) are longing for simpler times. Oh, for the days when Buckingham Palace had the wherewithal to keep its closet doors locked and its dirty laundry unaired.

Written and directed by British playwright Stephen Poliakoff, The Lost Prince tells — imagines, really — the haunting, little-known story of Prince John, the youngest of the six children of King George V and Queen Mary. (Some perspective for those who haven’t memorized the Windsor family tree: John’s brother Albert became King George VI, whose daughter is the reigning queen, Elizabeth II.) "Johnnie," who was born in 1905, had epilepsy and another unnamed condition that was probably some form of autism. Fearful that news of his "spells" and odd behavior would leak out, the royal family shipped the boy off to a country cottage near the palace at Sandringham, where he was raised in seclusion by his devoted nanny, Charlotte "Lalla" Bill.

The Lost Prince is a gorgeously filmed, bittersweet study of family dysfunction and the resiliency of the spirit in the face of loneliness and rejection. Throughout his short life, Johnnie (played as a youngster by the angelic Daniel Williams and as a genially unmannered adolescent by the gifted Matthew Thomas) keeps trying to make his way back to the palace and into the good graces of his family. But his parents, the king (Tom Hollander) and queen (an achingly sad, stoic Miranda Richardson), are visibly uncomfortable in their son’s eccentric presence — he says anything that pops into his head. Only the determined Lalla (Gina McKee) believes in Johnnie’s ability to learn, and she nurtures his musical and artistic talents.

It sounds sentimental, but it isn’t. Poliakoff is telling two stories here, and the interlocking of the personal and the political history of post-Edwardian England gives The Lost Prince astringency and depth. Johnnie’s life — he died in 1919 — coincides neatly with the passing of the dream of empire begun by his great-grandmother, Queen Victoria. At the time of Johnnie’s birth, a descendant of Victoria sat on the throne of every monarchy in Europe — the continent was one big happy family. In the surreally beautiful first half of The Lost Prince, Tsar Nikolai II of Russia brings his wife, the haughty Aleksandra, and their children to England to visit, and we see the imperial pomp and majesty in all its ridiculous glory. A red carpet is laid for a royal outing on the beach; when the tsar takes a dip in the ocean, the members of the two royal houses stand solemnly by and watch his silly dog-paddling. (Little Johnnie calls him an "emperor seal.")

Poliakoff is a witty, subversive filmmaker; in one scene, he re-creates a famous photograph of the two cousins, king and tsar, standing with linked arms and identical bushy beards and piercing eyes, and turns it into a ballet of indecision, as the two insecure leaders jockey for the more flattering position. There are also palace visits from cousin Willy, the German kaiser, as well as the other beruffled cousins who posed and played while the populist uprisings that would fuel World War I brewed under their noses. (Both installments of The Lost Prince are accompanied by the documentary The King, the Kaiser and the Tsar, which puts the mini-series’s events in historical context.)

At the end of part one, there is a striking image of dissolution as seen through Johnnie’s eyes. The boy has been allowed back to London for a visit, but his stay coincides with a crisis: Archduke Franz Ferdinand of Austria-Hungary has been assassinated, and King George V and his cousins are about to learn that blood is not thicker than politics. As Johnnie watches from a carriage window, a palace bureaucrat hurries up the steps to an urgent meeting of cabinet ministers, and a gust of wind tears his papers from his hands and scatters them around the courtyard in a snowy swirl. Everything has come undone. Just as Johnnie can never go home again, neither can the cousins who wear the interconnected, and increasingly irrelevant, crowns of Europe.