Imagine descending into absolute darkness, crushed by a mile of seawater, to a place that hasn’t seen the sun in four billion years. For Dr. Karen G. Lloyd, this wasn't just an adventure; it was a mission to find the "missing link" of life itself. In the mud of the deep seafloor, she discovered a world of "intraterrestrials"—ancient, slow-moving microbes that defy almost everything we thought we knew about biology.

In this episode of Mavericks of Science, we trace the journey of the girl who once knocked on a marine lab door at age 13 and grew up to rewrite the tree of life.