Colin Dexter's Inspector Morse novels, written between 1975 and 1999, became one of the most popular TV British series that ran from 1987 to 2000.

Dexter's 13 novels evolved into 33 TV movies, enhanced by the insightful performance of the late John Thaw as Inspector Morse.

Morse was a brilliant detective but a difficult person, moody, emotionally isolated from most people and totally devoted to his job. Viewers knew about his classic Jaguar, his penchant for crossword puzzles and his love of classical music, especially opera.

But we knew little else.

Even his first name was a mystery through much of the series. Morse used to joke that his first name was "Inspector."

Morse's first name was Endeavour, which is also the title of the highly entertaining Masterpiece Mystery! movie airing at 9 pm July 1 on PBS. (Check your local listings for details; it's also available on DVD.) Endeavor celebrates the 25th anniversary of the UK debut of Inspector Morse in 1987.

Endeavour shows rookie Constable Morse's first day on the job with the Oxford police in 1965. But this isn't just a remake of the classic Morse series or a prequel. Endeavour is as an insightful, complex tale as was the original one, showing us how Endeavour Morse would become Inspector Morse. And it's not exactly a smooth evolution as the young Morse is even more socially awkward and not as confident than his mature self.

But that brilliant mind was always there, and always working.

Endeavour's underlying theme is we all have to start somewhere. Is the person we are now the person we started out to be?

And as John Thaw showed the character's complexity, so does the intriguing Shaun Evans as the young Endeavour.

Evans delves into Morse's personality with panache. He is endearing and irritating; an old soul with a young man's concerns; emotionally fragile, he hasn't yet learned how to tamp down his feelings. The year is 1965 when the Beatles and the other great Brit bands were all the rage, but Endeavour prefers Puccini. His beat is Oxford, yet he dropped out from the university.

Endeavour arrives at Oxford with no car and little ambition. He thinks he wants to be a cop but isn't sure the force is right for him. And there is the matter of his queasiness at crime scenes. At his first dead body, he's admonished by the police pathologist, "You won't make much of a detective if you're not prepared to look death in the eye."

Looking death in the eye is what Morse ended up doing all his career and by the end of Endeavour he will learn to face the evil that people do without blinking, but with much regret.

Endeavour's first case involves a missing 15-year-old girl. He and his colleagues are called in from a neighboring town to help with the investigation, lead by Inspector Thursday (Roger Allam) who soon learns to appreciate Endeavour's unconventional mind.

Endeavour's hunches lead him to cryptic crossword puzzles, English Romantic poetry and clever disguises that no other cop thinks about. The plot works well and seeing Endeavour put it together is fascinating.

Without giving away any plot points, there are two inside jokes put in by director Colin McCarthy and scriptwriter Russell Lewis, creator of Inspector Lewis and writer of Inspector Morse. Abigail Thaw, daughter of John Thaw, the original Morse, makes a key cameo as a newspaper editor. When she meets Endeavour, she says, “Have we met?" When he says they haven't, she adds "Another life then."

Second, a brief moment in the very last scene shows that Endeavour knows exactly what his future holds, and he's okay with it.

Endeavour originally was to be the only episode about the young Morse. But four new episodes have been commisioned with filming expected to start this summer with a targeted 2013 airing.

Photos: Top and bottom, Shaun Evans as Endeavour Morse. Center, Shaun Evans with Roger Allam. Photos/PBS