The main problem with reviewing a thriller is the fear that you’ll give away too much and spoil it for potential audience members. That, and the stress that comes from trying to guess what the twist is while you’re watching. Stray Dog Theatre’s production of Peter Colley’s I’ll Be Back Before Midnight is so fraught with tension — oh, the tension! — that you spend too much time with your neck pulled into your shoulders. Director Justin Been drags your nerves down an ominous, tortuous path, occasionally detouring into a series of short, sharp shocks that knock the wind right out of your lungs.There are many layers at work here, chief among them our unreliable proxy, Jan (Angela Bubash). Fresh out of the hospital following a mental collapse, she’s been whisked away by her husband Greg (Jeff Kargus) to an isolated farmhouse so she can recover in the quiet countryside. Both of them fear that Jan is not ready to deal with the real world; any surprise or shock could tip her back into experiencing auditory and visual hallucinations, which will result in her reverting to a catatonic state. But from the moment they step into their country retreat (beautifully realized by Rob Lippert), it’s obvious that something strange is happening between the two of them. Jan attempts to discuss her nervousness about being out of the hospital and in a strange place, but before she gets three sentences out, her husband has headed upstairs with her luggage, oblivious to her fears — and to her. The sudden arrival of Greg’s sister Laura (Sarajane Alverson) pushes Jan closer to the edge; the two women don’t get along, and Jan blames Laura at least in part for her first breakdown. And then there’s the problem of the homicidal ghost that supposedly haunts the house. George (Mark Abels), the folksy and chipper farmer who owns the place, tells the couple all about an old murder and the resulting terrifying visitations that have scared every other tenant away. “There’s things that exist and things that don’t, and nothing in between,” George reassures Jan when he sees how deeply he’s unsettled her. “Some of us live our lives in between,” Jan answers, an early reminder that nothing she experiences — and that we see her experience — is certain to be real. Bubash is very good as Jan, her beautiful, expressive eyes always twitching around the room. Kargus is likewise excellent, his Jeff torn between supporting his wife, working on his thesis and maintaining his strangely familiar relationship with his sister. Alverson swans around in lingerie and smokes cigarettes disdainfully (a specialty of hers — there’s not a snootier on-stage smoker in St. Louis), dismissing Jan’s fears with aplomb. Abels’ George is a particular delight, spinning yarns and channeling his fondness for Sherlock Holmes into some light amateur detective work to allay Jan’s growing suspicions. Their unseen co-star is Justin Been’s aggressive sound design. Glass doesn’t break, it explodes; the shotgun on the wall blasts the daylights out of the darkness when it is eventually fired. Most effective is his lonely wind, which whistles around the eaves of the house when night falls and Jan is alone. You’ll grow to dread that wind and its mournful skirl — nothing good happens when it picks up. But that’s for me to know, and you to find out. Do bring a friend with you, though. That walk back to the car is awfully long when you make it alone, and whistling in the dark somehow makes it worse; too much like that damned wind, I suppose.