The Wind Gate begins with the dailiness of school life in Plymouth, but soon moves to the imagined ambiguities of Dartmoor, to stories of strange creatures and sudden death. Howard is a flabby boy unexpectedly befriended by stylish Steve. In bunking off from sports day to explore the apparition of the moor glimpsed in dreams and stories, irresolute Howard and decisive Steve change the nature of their relationship: the follower becomes the leader.

So much, so commonplace. But there’s a lot more to it than that. Out on the moor they meet Cali, a fey eccentric who disturbs Howard with her New Age lore - the Lyke Wake Dirge makes a haunting counterpoint to the bland satanism of the boys’ Heavy Metal craze - and her weird likeness to his soured anxious mother. He has a momentary vision of Circe which strangely encompasses them both: She’ll never let you go. But he escapes to the heart of the moor and the stone gate and the dim figure he is sure will be there.

The book has a deft metaphorical touch which makes these moments of insight both subtle and persuasive. Gross’s eye sees the moorland cattle shambling “like wardrobes on the move” the grey clouds “flat as slabs of slate, but the sun had prized them up.” As the book reaches its climax, with Howard alone on the numinous moor at night, it authoritatively blends thriller and poetry.

There are many themes developed in convincing parallel. Resonant chords of family life are struck from Howard’s envy of Steve’s cheerful home. There is a strong sense of bad past deeds touching across distances of time, and also a realisation of the traps built into language itself.

As a rescue helicopter carries Howard to safety at the end, he has a fuller sight of the moor and glimpses an enlarged terrain of possibility beyond the numbing continuities of his previous life. This is a book to be read at a gulp for its excitement and then again slowly to savour its thoughtfulness.

Nathan’s Switch touches many of the same areas of the imagination. Here is another adolescent boy with problems. Nathan’s parents are living apart, his mother is angrily trying to start a new career, his father angrily resenting her absence. Both are right and both wrong. Here too is an adroitly sketched mundane life at school and home changed utterly by the intrusions of the supernatural.

Nathan finds an abandoned gadget that proves to be a kind of time machine. But it doesn’t take him back to the past as himself; it forces him to experience the past through the eyes and body of the person who occupied the space he is in now.

This gives Nathan the means to produce a first-class history project and win at least one teacher’s approval. The direct experience of life under the Norman yoke, the huddled children, the mud, the choking smoke from burning buildings, the animal smells all these are vivdly described in a staccato interior monologue that carries conviction and then transcribed into a long narrative which Nathan reads to the class, bringing a new and tricky sense of self-esteem.

Time travel becomes a means of making sense of the confusions of growing up. Nathan remakes his life through understanding some of the forces that drive it. He sees his parents when they were young and in love. He becomes his mother suckling his own infant self. He experiences the war between men and women as well as that between Saxon and Norman, and realises how much depends on which side you’re looking from. But time travel also becomes a way of escaping from reality.

His life grows more stormy, he has a spectacular row at school and his parents evade fictional expectations and decide to divorce. Nathan is left at the end with a sort-of girl-friend, a sort-of reconciliation with his family and a sort-of acceptance that life will continue. But he’s also Nathan the Ready.

He remembers an infant teacher who encouraged the class to look closely at walls that were aubergine and amber, vermillion and fuchsia. A demolition worker shows him an 18th-century brick, still marked with the builder’s thumbprint. It’s an effective metaphor for the themes of individuality and relatedness that lie at the heart of a lively and reflective story.