When "The Young Indiana Jones Chronicles" returns on Saturday at 7 p.m. (Ch. 4), the two-hour episode is a perfect example of everything that's good and bad about the series.

This particular installment, titled "Young Indiana Jones and the Mystery of the Blues," is actually two different stories tied together by the time (1920) and setting (Chicago).In the first half, Indy (Sean Patrick Flanery) develops a passion for jazz - a musical form that, at the time, was confined to black Americans.

Jazz legend Sidney Bechet teaches Indy jazz, and the young man also learns about prejudice among both whites and blacks.

The narrative has a lot to say about race relations. It's thoughtful and effective without being heavy handed.

Unfortunately, it's also slow moving. Downright dull, sometimes, as a matter of fact.

There's some great music. As always, the production is handsomely mounted - almost theatrical in its lushness.

And the message is the sort of thing that young people should be exposed to.

Unfortunately, many of them probably won't sit through the first hour. It's just too slow.

That's a problem "Young Indiana" has had since it debuted on ABC early last year. Creator/

executive producer George Lucas often just can't seem to blend education and entertainment in sufficient quantities. Although the show drew big audiences when it premiered, viewers have tuned out by the millions.

Lucas has made no bones about the fact that education is his strongest motive. While, obviously, "Young Indy" is not historically accurate, Lucas' hope is to spark an interest in history among young people.

And Lucas has maintained from the beginning that the TV show is not a thrill-a-minute adventure like the theatrical "Indiana Jones" movies were.

Unfortunately, often the TV show episodes aren't even a thrill-an-hour.

Not that the potential isn't there. The second half of Saturday's episode turns into a murder mystery, which Indy sets out to solve with the help of his geeky college roommate, Eliot Ness, and his cub-reporter friend, Ernest Hemingway.

In addition to being a interesting puzzle, it's replete with running gun battles and much daring-do.

It doesn't have much to say about anything, but it's a lot of fun to watch.

If only Lucas could combine that kind of entertainment with the educational qualities he seeks to imbue his series with, "Young Indiana" wouldn't have been on a long hiatus - and wouldn't, in all probability, be a prime candidate for cancellation by ABC.

Adding it all up, the good far outweighs the bad on "The Young Indiana Jones Chronicles." But the bad could well be enough to sink the series.

In an effort to boost ratings, ABC is making much of the fact that Harrison Ford will reprise his role as Indiana Jones in Saturday's episode of "Young Indy."

But it's really not much to get excited about - three minutes at the top of the show, less than 11/2 minutes at the close.

Ford appears as 50-year-old Indy in 1950 Wyoming, where he's seeking to keep a valuable Native American peace pipe out of the hands of some bad guys.

There's a chase through the show, and Indy comes to a deserted cabin, where he finds a saxophone - calling up memories that become "The Mystery of the Blues."

And the ending is rather silly.

Ford's appearance is chiefly notable for two reasons. First, the 50-year-old actor is actually playing a character who's not a lot younger than he is.

And, second, there's a bit of John Williams' famous "Indiana Jones" theme at the end of the show - the only time you'll hear that music in the TV series.