The OA Season 2: What Does The Ending Really Mean?

In the finale, Hap explains his breakthrough to Prairie. He says that the multi-verse exists inside a seed in everyone’s brains, and something about being inside the puzzle House helps that seed sprout into a garden. Hap proclaims: "I didn't do this, the house did this. I'm just taking the opportunity to learn."

The garden itself – made up of the dead bodies of Scott, Steve, Jesse and French, with flowers growing from their brains and out of their ears – is actually a map to the many different dimensions of the multi-verse. He says their deaths are a terrible sacrifice, but these people are alive and well in other dimensions.

Eating petals from the garden offers a glimpse into the different dimensions connected to them. Hap says "All we ever had to do was to be able to imagine it to travel there." He explains this is what Prairie did when she thought of Homer when she jumped and it brought her here.