Full of encouragement to look up at the night sky with little children during these long dark evenings, Star in the Jar is about a small boy who loves collecting precious things – “Tickly treasure. Glittery treasure... even litter bin treasure” – and one day stumbles upon a real star.

Popped in a jar for safekeeping, the star never leaves the boy’s side, even brightening up a trip to the toilet. But as night descends, the star longs for home. Sarah Massini’s rich, characterful illustrations show the boy’s celestial friend growing limp as it gazes up from a window ledge to read a constellation spelling out “lost, one small star”. And so the boy and his big sister, the story’s narrator, must figure out how to return their latest treasure.

With its focus on the wonders of the night sky along with themes of loss and letting go, Star in the Jar is reminiscent of Coralie Bickford-Smith’s 2015 acclaimed debut The Fox and the Star. It also feels like a sequel of sorts to Oliver Jeffers’s How to Catch a Star, with the children here concocting various fun ways to send their catch back home.

But, while the stars dazzle, it is actually the love and friendship between the siblings, depicted by Sam Hay (author of more than 30 children’s books including the Undead Pets series) and illustrator Sarah Massini, which make this picture book such a magical read. Whether the brother and sister are curled up on a sofa, bouncing on a trampoline, or on the lawn trying to send illuminated messages skywards for the book’s magnificent climax, their bond shines out. A cheery, warm-hearted tale, beautifully told.

• Star in the Jar by Sam Hay (illustrated by Sarah Massini) is published by Egmont (£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