Tree-house designer Pete Nelson builds arboreal getaways that are large and ornate or small and simple in this series, which begins with a ranch-style structure in several hackberry trees on a property near Waco, Texas.

A Celtic-theme cottage in an olive tree in California features a circular design that includes a fireplace and a rain-maker to mimic damp Irish weather.

A spa retreat on a ranch in Texas presents Pete with several plumbing challenges when he makes room for a steam shower and a Japanese soaking tub.

A barn-theme tavern—complete with a brewing system—that's accessible by a rope bridge 25 feet high is constructed for a family in rural Ohio, and Pete gets help with the project from some Amish neighbors.

In search of an inspiring space to begin her first novel, a writer in Rhinebeck, New York calls on Pete to build a hideaway to embrace her creativity but instantly feels blocked when she disagrees with Pete about the chosen tree. Once Pete wins her over, he transforms the tree into a gold-leafed “Spirit House” retreat filled with Buddhist artifacts and uplifting oddities and a loft to rest the brain between chapters.

Episode Synopsis: A couple in Oregon need extra room when their daughter comes home from college, so Pete builds a guesthouse in a tree.

A family in Bedford, N.Y., spare no expense for a tree house that features a patio for barbecuing, a living room and a playroom with chalkboards.

In the Season 1 finale, Pete builds a honeymoon suite for a couple who want to get married at Treehouse Point, but all of the other accommodations are booked.

The “Treehouse Masters” team constructs a tree fort for a deserving family; Pete and the group recall their biggest challenges and most impressive builds.