Lisa Thompson’s The Goldfish Boy, about a troubled 12-year-old with OCD investigating the disappearance of a toddler, was one of 2017’s bestselling children’s debuts. Her follow-up, The Light Jar, is another mystery/thriller wrapped around psychological themes. Nate’s dad ran off with a colleague when he was six. Now 11, Nate and his mum are bedding down in an abandoned cottage, on the run from Gary, her emotionally abusive boyfriend. When his mother fails to return from a shopping trip, Nate must fend for himself – and convince Kitty, a girl who lives in the neighbouring stately home, that he has not been abandoned.

Domestic abuse is tricky territory for young readers (this is a “middle-grade” novel, as Americans have it), and there are moments here when Nate – and Kitty’s – predicaments feel almost unbearably bleak. There is a terrifying passage in which Nate has a panic attack in an enclosed space, and we come to understand his attachment to a jar filled with fairy lights that he keeps by his bed.

Plotting is Thompson’s forte – she deftly handles a thread in which Nate and Kitty solve clues from a decades-old treasure hunt, and her drip-feeding of details about Gary’s nastiness and Kitty’s tragic backstory had me rushing to turn the page.

Less successful are Thompson’s dips into magical realism. Passages in which imaginary friends turn up to help Nate navigate his troubles are presented as routine, with none of the transporting imagery of the best fantasy writing. But this is a thoughtful and hugely empathetic book: a consolation for readers who, for whatever reason, might be feeling a little out of place in the world.

• The Light Jar by Lisa Thompson is published by Scholastic (£6.99). To order a copy for £5.94 go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99