Premiere episodes are great because not only does it mean the return of your favorite series, but it's usually something that will be game-changing as well.

That has been the life of "Doctor Who" since it returned in 2005. But getting the attention of the first episode is easy. Still getting attention once you reach the midway point of a season ... that's hard. And "Doctor Who" showrunner Steven Moffat knows it.

"We're always trying to work out how to get Episode 7 coverage in the newspapers," Moffat recently told The Huffington Post. "Obviously, Episode 1 will [be written about], but how do you make [a later episode] a must-see?"

You do it by creating season splits, and adding key moments that will have fans talking all through the mid-season break, Moffat said. Last year, it was the revelation of who River Song is. This time, it's saying good-bye to Amy Pond and Rory Williams, played by Karen Gillan and Arthur Darvill.

"The event status of Amy and Rory leaving ... you feel tremendous pressure with that," Moffat said. "Because you don't know if you've enjoyed a story until it's over, and this is the ending."

But it has to be captivating for the audience, and they need to be tuning in. Otherwise, it will be hard to justify a big budget for "Doctor Who" in the future, Moffat said.

"There's a constant game of that, because 'Doctor Who' is an expensive show," he said. "It has to be very near the top all the time. That's tough to keep going."

Jenna-Louise Coleman is joining "Doctor Who," but not until the Christmas special. Then the second half of the upcoming season is expected to kick off in 2013.

"Doctor Who" itself is expected to return this fall on BBC One and BBC America.