An internationally renowned writer, Valeria Costas has dedicated her life to her work and to her secret lover, Martin Acla, a prominent businessman. When his sudden stroke makes headlines, her world implodes; the idea of losing him is terrifying. Desperate to find a way to be present during her lover's final days, Valeria commissions his artist wife, Isla, to paint her portrait - insinuating herself into Martin's family home and life. In the grand, chaotic London mansion where the man they share - husband, father, lover - lies in a coma, Valeria and Isla remain poised on the brink, transfixed by one another. Day after day, the two women talk to each other during the sittings, revealing truths, fragilities and strengths. But does Isla know of the writer's long involvement with Martin? Or that her husband had chosen Valeria for the years ahead? Amidst their own private turmoil, the stories of their lives are exchanged - and as the portrait takes shape, we watch these complex and extraordinary women struggle while the love of their lives departs, in an unforgettable, breathless tale of deception and mystery that captivates until the very end.