They're connected (it's more in my synopsis how i explain it.)
-Part 1: A Jewish father was suppose to die at Aushwitz but G-D, or what they think is G-D, reverses time for a year. A mysterious smuggler takes the Jewish family and Muslim Black family to Palestine to escape the holocaust written from the Jewish father's perspective.
-Part 2: About the children of the families and what they are doing. End of part 2 its revealed that G-D and nature are the same thing and that the smugglers are the guardians of nature. They have to interact with daily life if their is a threat to nature by somehow changing someone's fate that would then start a domino chain to protect all of nature.
-Part 3: 20 years after part 2: jewish son becomes a smuggler (or a guardian of nature) and helps rescue someone from North Korea..
so each part is connected, but each has its own plot/plots.