: In the modern day, Gavin, Izzy, and adult Lilly (Ella) locate a final, smaller sinkhole in Seattle. They take a literal leap of faith and successfully land in 10,000 B.C., where they are immediately greeted by a woolly mammoth.

: Just as the future is secured, the portal pulsates unexpectedly, snatching Josh , Riley , and Lilly away from 10,000 B.C. and transporting them to an unknown time (later revealed as 1988).

, titled "Topanga," is the high-stakes season finale of the first season of the NBC sci-fi series. The episode serves as a massive turning point, resolving the mystery of Gavin's origins while scattering the main characters across different timelines. Key Plot Developments

: During the struggle to rescue Isaiah from Silas, Marybeth is fatally stabbed. She dies in her son Lucas's arms just as they were finally reconciling their strained relationship.