People tend to skip over Sumatra when they travel to Indonesia. Bali is always their top pick. In North Sumatra lies Lake Toba, a hidden gem that intertwines historical and cultural allure.

I wanted to meet a medicine man. And Samosir Island in the middle of Lake Toba in northern Sumatra was the perfect place to look. So Molly and I set off with our guide Adi (while the boys opted to go ...