Based on the graphic novel by Scott Mitchell Rosenberg, Cowboys & Aliens follows Jake Lonergan (Daniel Craig), a criminal who awakens with no memories and with a strange bracelet on his wrist and its ending is surprisingly a bit complicated. It becomes clear that Lonergan is an outlaw who's guilty of many crimes and who many people would rather see imprisoned. When aliens arrive and begin killing and abducting the people of the small, Wild West town of Absolution, Lonergan teams up with Colonel Woodrow Dolarhyde (Harrison Ford), Ella Swenson (Olivia Wilde), other townspeople, and a tribe of Native Americans to defeat the aliens.

https://screenrant.com/cowboys-aliens-ending-explained/