Supreme Leader of North Korea had not been seen in public for a number of weeks, setting off a global frenzy regarding his whereabouts and health.

Speculation was rife as to who would succeed him.

The most likely candidate is his closest confidant. A young woman whose always by his side.

Becky Milligan pieces together the mystery of Kim Yo-jong. Politician and sister of Kim Jong-un.

Producer Smita Patel