There's no 'mystery' (to/as to/about) why we're here. = It's no 'mystery' why we're here. [=we know why we are here]
His success is something of a 'mystery'. = His success is a bit of a 'mystery'.
We'll reveal the identity of today's 'mystery' guest after these commercials.
(..) You move to the right... About goddamn time. If it takes all night Oh, come on, baby... Oh, you looking for JD? International Man of Mystery? 'Cause he's long gone, Baby. You got that right. Just put it down. We'll drink it. So, this is it. (..)2017 Baby Driver
(..) Ha! What the fuck? Soldier Boy. He ain't giving up, huh? I be a man, kinda mystery man... Come on, Soldier Boy. Shit! Ah! No, no, no, no! No! No! No! (..)2017 Baby Driver