As the podcast nears its conclusion, fresh information kept hidden in UK Foreign Office files for 40 years delivers yet another twist to this case.
Martin Bottomley of the Greater Manchester Police Cold Case Unit gives an unexpected reply to a question Dan hesitates to ask - and it becomes clear this story is far from over.
And Boston's public defender, Lexi Nagin, reveals she's an avid listener to the podcast - but hasn't changed her mind about her client.
Vince, Penny and Dan head out to the remote island of Hunting Caye, where Peta and Chris were last seen alive.
They find a near deserted paradise, far removed from any sense of danger. But as they sit and talk, Vince reveals disturbing new details about his father.
Leaving Belize and Vince behind, Penny and Dan go on to the port city of Puerto Barrios in Guatemala in the hope, more than expectation, of finding Chris and Peta’s lost graves.
What they discover at the cemetery leaves them with a creeping sense of unease about the information they'd been given – and the investigation the FBI led.
As Dan heads to Belize, hopes of finding Chris and Peta’s graves in Guatemala fade with new information about the lengths the FBI went to in their attempts to find them.
We meet Orlando, Dan’s Belizean fixer, who seems to know everybody in Belize by name as we begin to follow Chris and Peta’s steps. Peta’s letters start to come to life as we trace people and places she mentioned in her letters 40 years before.
Very few locals seem to remember Boston – but a visit to the factory Peta write about in her letters leads to a breakthrough in the investigation and Orlando’s experience as a mechanic proves pivotal.
Penny joins us in Belize to see some of the places her brother experienced on his travels with Peta in ’78 – before a memorable meeting in Belize City with Vince – the first time they have met. On board a near replica of the Justin B, Vince reconstructs the entire attack.
The episode ends with a conclusion to one of the podcast’s biggest questions – but a possibly bigger one remains.