For some, suburban life is a family’s dream. Take, for instance, the Ellisons. Mona has a lovely home; her husband, Ben, a successful child psychologist; their son, Gus; and her book club buddies right across the street. It’s everything she dreamed of. But dreams can be shattered in the blink of an eye.

After an argument with his dad, Gus disappears and Mona spirals into a terrifying emotional state. The book club ladies do all they can to support their friend, but Mona pushes against that, harboring suspicions that something sinister is going on with at least one of them. Ben tries to help with counseling and medication, only to be met with more suspicion. Mona becomes increasingly obsessed with finding Gus. To start, she turns to social media. There she comes across a message from someone calling themselves ICU2. Could it be Gus? Excited, she follows clues from this post --- and, later, others --- to wherever the message leads her. Mona just wants to talk to Gus and see if she can persuade him to come home.

"Be prepared for a twisty ride. And pay attention because the reality seems to change from chapter to chapter. Don’t miss this highly entertaining read."

Meanwhile, once again, Ben has pressing business that takes him out of town. Concerned about leaving Mona in this fragile state of mind, he nonetheless hops on a plane. He assures her that it’s only for a couple of days. For Mona, though, a couple of days may be devastating. A couple of days is more than enough time for her to create wild conspiracies, see mysterious visions and hear creepy noises in the night. In Ben’s absence, she even glimpses Gus and tries to reach out. Her mind takes her all sorts of places and conjures up weird scenarios that ultimately lead her into a very dark space.

One day, as Mona is struggling to cope, the doorbell rings. She answers, only to find a policeman on her doorstep. He tells her that a young woman named Mia has been killed. Might Mona know anything about it? Naturally, she claims to have no idea who Mia is, but of course she does. She remembers Gus mentioning Mia. Now more than ever, she must find him.

The shocker comes when we discover what happened to Mia and where Gus has been all this time. And did Mona actually know the young woman, or did she dream it? Is part of this a result of all those medications she’s been taking? Speaking of the meds, where did they come from? Has Ben been trying to muddle her brain, manipulating her into thinking she’s going crazy? All good questions. And all questions that will be answered. Just not until you reach the end. Mona will explain it to you. But she also will tell you that she trusts no one --- including herself. So can you?

Susan Furlong’s WHAT THEY DON’T KNOW begins with a happy scene: a book club of four friends enjoying themselves. From there, the story takes a long, precipitous slide into darkness. Be prepared for a twisty ride. And pay attention because the reality seems to change from chapter to chapter. Don’t miss this highly entertaining read.