Sarah and John were married. Each had children from before the marriage. One of Sarah’s children, Gary, predeceased Sarah, leaving children of his own. In 1984, Sarah and John executed nearly identical wills, leaving all of their property to the survivor, and, after the survivor’s death, to both of their children in equal shares, with Gary’s share going to his children. John died. In 1993, Sarah executed a new will, which revoked her 1984 will, and directed that her estate be divided equally between her children, with nothing going to John’s children. Following Sarah’s death, John’s children (plaintiffs) filed suit, and Gary’s children (third-party plaintiffs) intervened, alleging that Sarah’s 1993 was ineffective to alter the bequests in the 1984 wills because Sarah and John’s 1984 wills were contractual. The attorney who drafted the 1984 wills testified that Sarah and John wanted to execute contractual wills, wanted their property to be divided equally between both of their children, and wanted to prevent the surviving spouse from changing the shares to the deceased spouse’s children, but wanted the surviving spouse to have the right to alter the shares to his or her own children. The district court admitted the attorney’s testimony regarding the agreement between Sarah and John. The district court held that the 1984 wills were contractual and that Sarah’s 1993 will was therefore ineffective to alter the shares to John’s children, although she could alter the shares for her own children. The district court imposed a constructive trust on the estate in favor of John’s children, in the amount they would have received under the 1984 wills. Sarah’s children and Gary’s children appealed.