Mercury Investment Co. (Mercury) (plaintiff) leased space in its multi-tenant shopping center to F.W. Woolworth Co. (Woolworth) (defendant) in 1959. Under Mercury’s merchandising plan, Woolworth was intended to be an “anchor tenant” that would attract shoppers for the mutual benefit of all the shopping center’s tenants. Woolworth’s lease was for fifteen years and provided for an annual minimum rent of $19,350 for the first 14 years and $17,425 thereafter. It also provided for additional rent, calculated by taking a percentage of Woolworth’s gross receipts in excess of a specified base amount. Woolworth’s gross receipts never exceeded the specified base amount and therefore, Woolworth never paid additional percentage rent. In 1981, Mercury brought suit to terminate the lease with Woolworth, arguing that Woolworth breached an implied covenant to diligently operate its business in order to generate percentage rent and to attract customers to the shopping center. The trial court granted summary judgment in Woolworth’s favor. The Court of Appeals reversed.