Pentatonix is coming back to NBC for the group's third holiday special – and this time, a bit of (cheesy) mystery.
The holiday special, titled "Pentatonix: A Not So Silent Night" (Monday, 10 EST/PST) follows the a cappella group through a mysterious stay in Las Vegas on Christmas Eve.
To help you get ready for the music-filled mystery, we've rounded up everything you need to know:
What's the special about?
Viewers follow the group as they retrace their steps in Las Vegas to figure out what happened during their "Not So Silent Night" on Christmas Eve – all while performing musical covers, of course.
The special begins in their Caesars Palace hotel room, where no one, except newest member Matt Sallee, knows why they're dressed in strange attire (vocalist Scott Hoying is wearing a gladiator costume).
As Sallee begins to explain, flashbacks reveal the previous day's events, and shows off several tourist spots where the group breaks into musical numbers.
Some locations include the High Roller ferris wheel, where "Joy To The World" is performed, and Penn and Teller theater ("Sweater Weather" and "Coldest Winter.")
Who else is in the special?
Throughout the special, the group meets up with three other artists to perform songs: A 10-part harmony with The Backstreet Boys on "Winter Wonderland;" a sing-along with Kelly Clarkson of her "My Grown Up Christmas List" and two songs with country star Maren Morris. Whitney Houston's "When You Believe" and Jeff Buckley's "Hallelujah."
What other songs do they perform?
Pentatonix also performs "What Christmas Means To Me," "Rockin' Around The Christmas Tree/Deck the Halls," "Where Are You Christmas," "Making Christmas" and "Jingle Bells."
This article originally appeared on USA TODAY: Your guide to Pentatonix's latest NBC holiday special, 'A Not So Silent Night'