John A. and Agnes Gassmann established identical trusts: the John A. Gassmann Revocable Living Trust and the Agnes M. Gassmann Revocable Living Trust (parent trusts) (plaintiffs). The couple’s assets included farmland deeded to the John Thomas Gassmann LLLP (LLLP). The parent trusts each held a 49.5 percent interest in the LLLP. The remaining one percent interest was held by the couple’s son, John T. In addition to John T., John A. and Agnes had three other children: Mary Reichert, Jo Anne Dalhoff, and James Gassmann (defendants). Article Ten, Paragraph 2 of the parent trusts set up trusts for each of the children. Article Five, Paragraph 6 of the parent trusts detailed the distribution of LLLP assets, with each trust stating in Paragraph 6(a) that if John T. survived the decedent, the trust’s LLLP interest would “be handled pursuant to Paragraph 2 of Article Ten.” Paragraph 6 further provided that if John T. did not survive the decedent, the parent trusts’ LLLP interest would go to John T.’s descendants and that if neither John T. nor any of his descendants survived, the LLLP interest would become part of the residue of the trust estate. After John A. and Agnes died, their children disputed how the LLLP assets should be distributed. The attorney who had both formed the LLLP and drafted the parent trusts asserted that Paragraph 6(a) contained a mistake and that John A. and Agnes intended the LLLP assets to go exclusively to John T. The attorney had taken handwritten notes to that effect when he interviewed John A. and Agnes about the establishment of their trusts. The trustee for the parent trusts petitioned a district court in North Dakota to reform the trust provisions. Mary, Jo Anne, and James opposed reformation, contending that the trust provided for an equal distribution of assets—including LLLP assets—among all children. The district court concluded that reformation was proper to effectuate the settlors’ intent and that, after reformation, John T. was entitled to the LLLP farmland in addition to one-fourth of the remaining parent-trust assets. The defendants appealed.