H. N. and Vera Warren (defendants) developed and built the Warren Subdivision. The Warren Subdivision had three adjoining residential neighborhoods known as units. In Unit One, seven of the nine deeds were restricted to residential use. In Unit Two, 13 of the 21 deeds were restricted to residential use. In Unit Three, 12 of the 20 deeds contained similar restrictions. Further, the Warrens had orally informed prospective buyers that only single-family homes would be constructed and that no apartments would be constructed. Buyers relied on these statements in deciding to purchase from the Warrens. Indeed, when buyers made their purchases, there were only single-family homes in the Warren Subdivision. But the Warrens later sought to construct two duplexes on lots in Unit 3. Mike Detlefsen and other homeowners in the Warren Subdivision (plaintiffs) filed suit to enjoin the construction of the duplexes. The trial court enjoined the Warrens from building the duplexes, finding that the lots were restricted to single-family homes. The Warrens appealed.