Some science-fiction stories have been deployed so frequently that it seems as if they might be utterly exhausted. The ‘first contact’ narrative is one such: aliens arrive on Earth and are either malevolent (go, humanity!) or peaceful, whereupon we silly primates act aggressively towards them (oh, humanity!). It is therefore especially commendable when a writer is able to take such a tried and tested narrative and find something new, enlightening and bold in it. Nnedi Okorafor’s Lagoon manages just that, and disrupts the standard alien arrival clichés in numerous ways.

First, the aliens arrive in Lagos, rather than Washington, DC, or London or New York. Secondly, the first contact isn’t with humans at all – in a lyrical overture to the novel proper, a fish has that privilege, and what it does with the wishes granted to it is both