An expert in oxytocin, the hormone released during birth, Bianca Jones Marlin is determined to have a natural birth, and science writer Veronika Meduna thought she never wanted to have children, but in her late thirties, she changes her mind.

Born without a right pectoral muscle, John Trumbo has always felt defective, but then he discovers a possible solution, and Emma Yarbrough discovers there’s more to her unusual height than she’d thought.

Erik Klemetti starts to question his decision to become a geologist when a 20,000-foot volcano in Chile, proves difficult to tame, and explorer George Kourounis prepares to enter a fiery sinkhole known as the “Doorway to Hell.”

Science writer Kate Sheridan falls in love with a man who suffers from paralyzing headaches, and math teacher Giselle George-Gilkes is on a trip with her students when she receives terrible news from home.

Gail Thomas clashes with her oncologist while deciding how to fight her cancer, and as a marathon runner, Pierce McManus prides himself on his toughness — but then he begins coughing up blood.