Diane has a dark secret, one that she’s told her school friend Kit. Like a Spielbergian shark, it is hinted at several times long before its arrival about half way in, but you’d want to be in an awful stupor not to cop what’s going on, what with the girls studying Shakespeare in front of you. Years later these two highly intelligent and ambitious women are part of a research group into premenstrual dysphoric disorder, a condition that can, we’re told, result in violence amongst the affected. The disorder is referred to by one female character as the “dark continent” in the text, and, less charitably, as “Hatchet PMS” and the “Medusa menses” by the male co-workers.

The competitive relationship between the two main characters, as they vie for attention/recognition from charismatic project leader Dr Lena Severin, harks back to Addy and Beth and their cheerleading coach in Abbot’s 2012 novel Dare Me, although this book speaks more of forced female competitiveness, and rage, in a patriarchal world.

Despite the plot signposts this is a highly effective thriller, especially in its second half when things really kick off. Kit lets the secret slip, setting in motion a chain of events that brings the true nature of the Diane’s fragile/frightening personality – “the slow gathering of hot blood” - out in the open.