This is Elly Griffiths best novel to date. In The Frozen People, she introduces the aspect of time travel, which adds a surprising twist. Ali Dawson is a London detective in the cold case unit, when she is requested by a Member of Parliament to work on a specific case. MP Isaac Templeton wants Ali to clear the name of an ancestor, Cain Templeton, from rumors that several women he knew disappeared and/or were murdered. But Ali must be transported back to 1850 in order to work on the case. Planning on being there for a short amount of time, she misses her portal back and is stuck there for longer than she planned on. While she is there, a woman in her guesthouse is murdered, and back in 2023, her son is accused of a murder. Can Ali find enough evidence to clear Cain Templeton before she travels forward to her normal life in order to prove her son is innocent?