In December 1991, Michael Paxton and Amy Lowder (tenants) (defendants) rented an apartment from Building Monitoring Systems, Inc. (landlord) (plaintiff), who was in the business of renting out units in its multi-unit apartment building. Soon after taking possession, the tenants notified the landlord that the apartment required repairs. Although the landlord made some minor repairs, the apartment remained in violation of Health Department regulations. On August 9, 1993, the tenants reported the violations to the Health Department. In turn, the Health Department sent the landlord a letter ordering the landlord to make repairs by September 7. Instead, the landlord served the tenants with an eviction notice. However, the landlord reinstated the tenancy when it subsequently accepted the tenants’ rent for October. On October 12, the plaintiffs sent the landlord a list of needed repairs and complained again to the Health Department. The day after the landlord received notice from the Health Department regarding the tenants’ second complaint, the landlord served the tenants with another eviction notice. When the tenants refused to leave, the landlord brought this unlawful detainer action. The tenants submitted the defense of retaliatory eviction. The trial court agreed that the eviction was retaliatory but refused to recognize the defense because it had not previously been recognized in this jurisdiction.