Testator's will devised all his property to his wife and 'her heirs and assigns.' His wife predeceased him. After his death, Testator's stepchildren (P) entered a contract to sell a house owned by Testator, claiming title as the heirs of Testator's wife. The buyer (D) refused to perform under the contract, arguing that, because Testator's wife predeceased him, P took nothing under the will.