A boy; haunted, shaken and scared. Fractured sentences. Guarded looks. A twist of the mouth, more grimace than smile. An offer to follow in pairs.

We are in the dark. Literally. With the wreckage of RMS Titanic and the Lost City of Atlantis scattered around a gangplank of concealed ladders.

It may be a cave, it may be a bunker. But wherever it is there is no welcome mat and it feels the opposite of home.

An adult male raises his voice and issues a threat. Violence is certain.

In fear of his life, the boy takes to his heels to a clanking soundtrack of panic, which comes to an abrupt halt when a young girl stops him in his tracks.

A danger? A saviour? A fellow lost soul? Throughout the course of a riveting hour, he’s never really sure. And, in truth, neither are we.

But a friendship of sorts emerges in their nightmarish underworld of red-eyed robots and flashes of violence as they push and probe and prod one another for answers as to where they are, how they got there and whether they can return home.

A gnarled ball of Missing posters hanging from the ceiling like a wasps’ nest suggests no.

The Lost Things by playwright Oliver Emanuel and the Edinburgh-based theatre company Tortoise in a Nutshell is a wonderful enigma which is performed with great subtlety and boldness by Arran Howie and Alex Bird.

Combining puppetry, multiple miniature props, an immersive domed set and a powerful soundscape by Jim Harbourne, it dares to go where few shows for children and young people go. Bad things happen, wrongs can’t always be righted and sometimes there are no easy answers.

But there is always hope. And the possibility of friendship. Which are the rocks the unnamed boy and girl cling to as they attempt to climb from the hole into which they have fallen.

Peter Callaghan