She had put the card into her bedside table drawer, and then taken it out again to use as a bookmark later that night for the thriller she was reading, a twisting tale of revenge and murder set on a trawler in the Norwegian fjords. A global bestseller featuring a yearning relationship between the married captain and his secret lover, the book had been a gift from Stephen that Esther had been consuming avidly, thrills of recognition flaring at every mention of the captain’s forbidden passion. That night, however, her thoughts kept drifting to her new bookmark, to the sort of man who would choose to devote his life to the study of things like knights and damsels and courtly love; and to the word spellbound.

‘I am with someone,’ she blurted out to Lucas three weeks later, persuaded to meet in a small Italian place near her flat, after two more postcards and a phone call to the Cambridge number originally undertaken with the intention of achieving the opposite outcome. The new cards had been themed similarly to the first, both arriving in envelopes, on consecutive Fridays, one depicting a knight trying to pull an arrow from his heart, with a speech bubble saying, Aaagh, the other emblazoned with the words, ‘Nothing is sweeter than love’, apparently said by some medieval cleric called Thomas à Kempis.

‘We have been together almost a year now, and it really is serious,’ she went on solemnly, having seen no option but to explain the Stephen situation fully. ‘I’m sorry, but just meeting you tonight feels a bit… wrong… which I hope you can understand because…’ Esther dried up, in a fresh confusion about having agreed to the date instead of sticking to her guns on the phone, and because ever since picking her up from her doorstep, Lucas, for all the implications in his correspondence, had been notably amiable rather than ardent. It had even occurred to her that this second encounter – with the reality of her, as opposed to some overblown memory of a brief conversation behind some bookshelves – had caused his feelings to retreat.

‘Friendship with another person can’t be wrong, surely?’ he replied coolly, twirling spaghetti round his fork before raising it to his mouth. ‘Or does Stephen not allow that?’ The fork disappeared cleanly between his even teeth and he chewed slowly, watching her with fixed, inscrutable eyes.