Welcome aboard The Sacramentum. New recruit Jamie Walsh gets a crash course on ship life while trying to keep a low profile as he investigates what happened to his missing sister.

After shocking news concerning a chief suspect, Jamie and new friend Vivian work together to discover the identity of an officer onboard who was connected to his sister.

Jamie becomes embroiled with an illicit operation on board in exchange for new information on his sister. Meanwhile, Vivian is charmed by a guest as another crew member vanishes.

After an unlikely ally reveals new information on Pippa's last days on board, Jamie and Vivian make a shocking discovery that leads to a dangerous confrontation.

Jamie finds himself in a lethal dead end with seemingly no way out. But after a surprise intervention brings some momentary respite, he learns that others are in peril.

Jamie becomes a fugitive onboard, forcing his friends to hatch a daring plan, one that leads to Jamie discovering the truth about what is really happening onboard.

Back on land, Jamie and Vivian are fighting hard to expose Velorum. But the walls are closing in, and they’re forced to take desperate measures. In a deadly gamble, they set their sights on Velorum’s newest venture – an exclusive 'wellness' festival in Slovenia.

A bombshell reunion separates Jamie from his friends and puts him in grave danger, while the rest of the gang get to grips with the eccentric festival. Soon, everyone finds themselves drawn into an unwanted encounter with an old foe.

As the past comes back to haunt him, Jamie goes rogue and makes a terrifying, inhuman discovery. Meanwhile, an old adversary makes their presence known.

As the full horror of the festival becomes clear, there may be no going back for Jamie when he is faced with a final, nightmarish choice.

After the group decide to go their separate ways, Jamie and Vivian must delve deeper to find the missing festival staff, forging new alliances along the way. Meanwhile, the gang on the road become lost and find themselves caught up in a terrifying siege.

As devastating news reaches Jamie and Vivian, their morals are put to the test as they face what it will take to win the battle against Velorum.