The reporter takes up his handy-dandy notebook and records these observations:

1. A heavy reliance on the color blue. 2. Features a boy and his dog. 3. Theme song teaches that "when we use our minds, take a step at a time, we can do anything that we want to do."Hmmmmmm. Even a grown-up could deduce this must be "Blue's Clues," the TV series that challenges its pre-school audience with such mysteries as what game does Blue the puppy want to play, and what can her owner, Steve, do to treat a head cold?

Since its launch on Nickelodeon two years ago, this daily bluedunit has become the highest-rated pre-school show on commercial television, its deliberative pace giving paws to 4.7 million viewers per week.

"Blue's Clues" repeats one episode Monday through Friday at 7:30 a.m. MDT and a different one at 10:30 a.m. EDT. The repetition gives every kid the chance to master each episode's challenges.

But in a special prime-time premiere Sunday at 6 p.m. MDT, Blue celebrates her birthday. There's a party, of course. And Steve confronts the problem of what gift this discerning pooch wants.

Clues: 1. It's green. 2. It lives in a glass terrarium. 3. It has a shell. With his crayon Steve logs these findings in his handy-dandy notebook. His soulful eyes betray uncertainty. Will he crack this mystery in time?

The success of "Blue's Clues" is no mystery to Brown Johnson, Nick Jr. senior vice president.

"We made a show that worked the same way as little kids watch," she says. "They talk to the TV, they point, they interact. Then we ask them to think really hard."

"Each script actually contains three games," notes Angela C. Santomero, a co-creator of "Blue's Clues" and its head writer, "and each one of the games has three layers within them - smaller problems for pre-schoolers to solve."

To be specific, youngsters are invited to assist the literally clueless Steve, who never seems to notice his pet's iridescent paw print targeting each clue - at least, he doesn't notice without a little prompting.

"I can tell I'm gonna need your help," Steve says imploringly into the camera. "Will you help me?"

Steven Burns, the 24-year-old actor who plays the cleverly named Steve, is in a tiny production studio in Tribeca. He wears Steve's nerdy khaki slacks and green-striped rugby shirt - Gap gone awry. But just about everything else is . . . blue. He stands on a blue floor, in front of a blue background.

Adding to the other-worldly atmosphere, Steve is talking to co-stars that aren't there, miming precise interaction with objects that won't be added for weeks. The absent Blue's comments (squeaky variations on "pah-pow!") are fed to him by a production assistant.

There is one actual, touchable prop: the plush red Thinking Chair, to which Steve repairs for pondering his clues. It came from a furniture store.

But Blue, her canine friend Magenta, the shaker couple Mr. Salt and Mrs. Pepper, and Mailbox - they, as well as the virtual cottage that Steve calls home, are all created from handmade objects digitally scanned then animated on Macintosh computers.

For example, the character Shovel started out as a clay figure about three inches high. Then color, texture, facial features were electronically added. It's a process that Traci Paige Johnson, another co-creator as well as the show's designer and Blue's voice, calls "yummifying, where you want to touch everything and play with it."

Which you do. The show's resulting look is that of a storybook come to yummy life.

Meanwhile, life at the studio isn't so yummy. "I'm the only one," Burns says during a break in a 10-hour shooting day. "It's never anybody else's turn."

At least not yet, agrees executive producer Todd Kessler. Months from now, when the finished episode airs, it will be the audience's turn to get involved.

"We want to integrate the viewer as one of the protagonists," Kessler says. "And since men don't usually ask for help from kids, when Steve asks them for help, it's especially inspiring."

In Burns' mind, Steve is not so much an adult as a big kid who's happy to play with little kids. "Then I become completely insane and imagine the characters being there."

But fortunately, Burns is a dog lover. All the better if she's blue.