KATHY BRYAN LOVED the idea of owning a mid-century modern home on Cape Cod. However, the property she purchased four years ago with her husband on Mystic Lake in Marstons Mills was more stuck-in-the-’70s relic than architectural gem. That is, until David Eisen, principal architect at Allston-based Abacus Architects + Planners, took charge.

Bryan and her husband used to rent on the Cape almost 40 years ago, when she was in law school at Northeastern. When they relocated from Chicago to New York City in 2008, the couple took advantage of their newfound proximity to buy there. “It will be our retirement home,” she says. “I wanted a house on a lake, and he wanted a place on the Cape, so it’s the perfect compromise.”