Mae pawb yn colli rhywbeth i’r Tox; collodd Hetty ei llygad, mae llaw Reese wedi newid, a diflannodd Byatt.

Mae deunaw mis ers i Ysgol Raxter i Ferched gael ei rhoi mewn cwarantîn. Trodd y Tox y myfyrwyr yn rhyfedd a milain a bu farw’r athrawon. Nid yw’r merched yn meiddio crwydro heibio i ffens yr ysgol lle mae’r Tox wedi gwneud y goedwig yn wyllt a pheryglus.

Maent yn aros am y gwellhad wrth i’r Tox cymryd eu cyrff. Ond pan aiff Byatt ar goll, bydd Hetty yn gwneud unrhyw beth i ddod o hyd i’w ffrind gorau.

Everyone loses something to the Tox; Hetty lost her eye, Reese’s hand has changed, and Byatt just disappeared completely.

It’s been eighteen months since the Raxter School for Girls was put in quarantine. The Tox turned the students strange and savage, the teachers died off one by one. Cut off from the mainland, the girls don’t dare wander past the school’s fence where the Tox has made the woods wild and dangerous.

They wait for the cure as the Tox takes; their bodies becoming sick and foreign, things bursting out of them, bits missing. But when Byatt goes missing, Hetty will do anything to find her best friend, even if it means breaking quarantine and braving the horrors that lie in the wilderness past the fence. As she digs deeper, she learns disturbing truths about her school and what else is living on Raxter Island.

And that the cure might not be a cure at all…