仙婿King, a trafficked lion cub, escapes from the airport in mid-transit and finds shelter in the home of Inès and Alex, 12 and 15. The siblings come up with a crazy scheme: to bring King back to Africa. Unfortunately, the customs agents on their tail don't make their mission easier. But soon, Max, the kooky grandfather they've only met twice before, joins their adventure... and from then on, the sky's the limit.