This is a flashback episode. It explains how Eliza and Darwin met. It also explains how Eliza got her power to talk to animals. This episode has events that has happened two years prior to the start of the series.
The episode starts out with Eliza as a ten year old wandering through the jungle. Then she apparently gets eaten by a giant python. Darwin supposedly saves Eliza from the snake.
Participating Burger Kings would give out cards for kids to mark the animal's places for each episode that aired in a lead-up to the episode's premiere, and a 1-800 number would appear. Kids had to dial this number and report their locations to the anonymous caller, and he/she would give out a trip around the world for the Grand Prize winner.