NBC wants to make sure “The Mysteries of Laura” isn’t a mystery to potential viewers, slotting a special sneak preview episode behind its biggest summer show.

“Laura,” which stars Debra Messing as an NYPD homicide detective who balances her day job with a crazy family life, will now first air at 10 p.m. Sept. 17 — one week earlier than planned — following the season finale of top-rated summer series “America’s Got Talent,” the network announced Wednesday.

It will then make its regular-timeslot premiere at 8 p.m. the following week, on Sept. 24.

With the Wednesday 10 p.m. dramas on ABC and CBS not bowing until Sept. 24, “Laura” will get a chance to be sampled with both the benefit of a strong lead-in and also against soft-ish competition.

“The Mysteries of Laura” is a production of Warner Bros. Television, Berlanti Productions and Kapital Entertainment. The cast also includes Josh Lucas, Laz Alonso and Janina Gavankar.