"Inspector Morse" is one of those great British mysteries that PBS has made a staple. Sometimes though, the universe in which a character lives has to be expanded. That is what is happening here with "Endeavour." The new series features a young Morse, still a Detective Constable instead of an Inspector. This young Morse is already great at solving a mystery, but doesn't yet have all the various affectations of the older version (i.e., no red Jag). Tune in tonight for the start of the series and see how it all began... or begins. The program airs as a part of PBS' "Masterpiece."