Surrogate is a nasty bit of horror with cool ideas and the confident craftsmanship to convey them.

It’s a ghost story about an Australian nurse Natalie Paxton (Kestie Morassi), who is also a dedicated single mother to Rose (Taysha Farrugia). It’s hard on Natalie, but thankfully she has family to help out. Her brother, William (Darcy Kent), and mother, Anna (Louise Siversen), watch Rose while Natalie travels once a month to help at a clinic in rural Borden — a four-hour round-trip away from home.

Late after one shift, Natalie encounters a strange, babbling, vomiting woman in an alleyway. Soon after, she starts experiencing strange events. Paranormal activity, you might say. Natalie and Rose become the center of a haunting that seems determined to take their lives and the lives of those around them.

I was pretty impressed with Surrogate, which adeptly balances build-ups and payoffs throughout the film’s story. One of Natalie’s first experiences is a phantom birth. She wakes up screaming in the night covered in her own blood, only for a doctor to tell her she’s hormonally pregnant even though she’s been abstinent for several years … and there’s no sign of a baby. Even the doctor admits she’s a complete anomaly. It’s a horrifying moment and just the start of the film’s approach to twisting the knife into its characters in unique ways.

After the phantom pregnancy, Natalie comes under suspicion by child services. She’s pursued by skeptical agent Lauren Balmer (Jane Badler), who fears for Rose’s safety and scoffs at the idea something supernatural is afoot. It should be noted for viewers with a sensitivity to seeing children in danger that this film really does go there, albeit tastefully.

Natalie starts investigating and finds herself in a race against time: Can she uncover the origin of her tormentor before it manages to kill again? And why is it so focused on Rose? All of these questions are answered, of course. The script by Beth King and David Willing (who also directed) is tightly wound. Plenty of horror films are content to build a story around a series of specific, memorable scares even if it means the characters and motivations only exist to further the kills. That’s not the case in Surrogate, which plays out a compelling mystery that just happens to be about ghosts, murder and the occasionally successful jump scare.

My favorite sequence is a quasi-exorcism using mirrors and a little girl who can communicate with the spirit. It’s tensely paced, beautifully designed and a creative depiction of a ritual we’ve seen cinematically countless times. Seeing something familiar done in a new way is always exciting, particularly when it’s this good.

Surrogate is also so centered on Natalie that it would fail without the right casting, and thankfully Morassi pulls it off. There’s a scene at the end, in particular, that she kills.

Speaking of the ending: I would never spoil the details except to say that I felt very strongly when the credits rolled. A lot of horror films run through the motions or provide momentary thrills at the expense of emotional involvement. That’s not the case with Surrogate, which put me through the wringer thanks to how well-written Natalie and Rose are. The highest praise I can give a horror film — which I wholeheartedly dole out here — is that I’ll definitely be thinking about this one for a little while.