The Houston Grand Opera is currently alternating two very different musical dramas, Puccini’s Tosca and Britten’s The Turn of the Screw. But despite their dissimilarities, Houston has managed to link the two atmospherically.

It does this by making Tosca a little more spooky than usual (The Turn of the Screw is spooky enough to start with). Of course, an opera that includes a murder, a mock execution turned real, and a suicide — as Tosca does — should be kind of creepy, but that effect has long since been diluted by countless repetitions. So Houston brings in a prisoner in the last act, puts a noose around his neck and hauls him up to near the top of the stage, where he twists slowly, slowly in the wind until the opera’s over (I’m hoping the condemned was a dummy, and not some poor super). And at the end Tosca cuts her own throat rather than leap over the parapet.

This certainly adds a little darkness of vision to the production, as does Bunny Christie’s sets, which project a sense of decay. The church, Scarpia’s apartment and the fortress prison all are framed by a rather dilapidated stage-filling box of grim color. Scarpia’s place is packed to the rafters with crates and statuary. Apparently he’s a kind of proto-Hermann Göring, collecting looted art.

And then there’s the increasingly blood-red drapes, which billow to the floor when various characters tug at them (once swallowing poor Scarpia in yards of cloth). As well as the ghostly young girl in white who mysteriously (and silently) appears from time to time and finally becomes the shepherdess in the last act.

Not quite a conventional Tosca, but all this did add a little zip to what was in other respects pretty conventional. A decent cast — Patricia Racette (Tosca), Alexey Dolgov (Cavaradossi), Raymond Aceto (Scarpia) — creative direction by John Caird, and superb playing by the Houston Grand Opera orchestra under Patrick Summers’ musical direction made it a worthwhile three hours or so.

The Turn of the Screw is the latest entry in Houston’s multiyear survey of the operas of Benjamin Britten.

It is, as I said, a spooky opera — you’re never quite sure whether the ghosts are real or just the fevered imaginings of a governess who’s slowly losing her mind. The ghostliness is reflected in Britten’s music and in Houston is enhanced by Stephen Curtis’ brooding sets, in which dark rotating elements with distorting mirrors move about to form various rooms and other spaces. (There are also cloths that fall when pulled on — did Curtis and Christie compare notes?)

A topnotch cast of stagewise performers includes Amanda Roocroft (the governess), Andrew Kennedy (Quint), Joélle Harvey (Flora), Michael Kepler Meo (Miles), Judith Forst (Mrs. Grose) and Tamara Wilson (Miss Jessel). Effective direction is by Neil Armfield and Summers conducts the chamber orchestra.

This one is definitely worth the time. Performances continue through Feb. 13 (Tosca is sold out).