Hunanladdiad yw'r rheithfarn swyddogol yn dilyn darganfyddiad corff mewn ardal anghysbell ar arfordir Ynys Môn. Mae DI John yn amheus ac yn credu fod grymoedd cudd y seiri rhyddion ar waith. Twyll yr heddlu, cam-drin domestic, anghyfiawnder i ferched a marwolaethau amheus - yn dilyn Y Milwr Coll, dyma ddirgelwch nesaf yr heddwas maferic DI John o Ynys Môn. Suicide is the official cause of death when a body is found on a secluded part of the Anglesey coastline. DI John has his suspicions and believes that hidden forces are at work. Police deception, domestic violence, injustice and suspicious deaths - following Y Milwr Coll, this is the next case for maverick policeman DI John from Anglesey.