Shark!

Celebrities brave a nerve-wracking swim across shark-infested waters before attempting a Bahamas scuba dive, which turns dangerous when one encounters trouble underwater.

The celebrities deal with the aftermath of a medical emergency, and then attempt the Line of Terror - which brings them eye to eye with Caribbean reef sharks in the middle of a feeding frenzy.

The celebrities face their toughest test yet, pushing one person to their absolute limit. Later, the group is left shocked by the reveal of their next challenge.

After conquering a terrifying night dive, the celebrities scuba dive with great hammerheads, but after the dive takes a terrifying turn, one celebrity makes a shocking decision.

The mission to better understand sharks comes to an emotional end as the celebrities come face to face with tiger sharks in the ultimate once in a lifetime final dive.