An injury is inherently undiscoverable if it is, by its nature, unlikely to be discovered within the prescribed limitations period despite due diligence. S.V. v. R.V., 933 S.W.2d 1, 7 (Tex. 1996) (citing Altai, 918 S.W.2d at 456). "Inherently undiscoverable" does not mean that a particular plaintiff did not discover his or her particular injury within the applicable limitations period. Id. Instead, we determine whether an injury is inherently undiscoverable on a categorical basis because such an approach "brings predictability and consistency to the jurisprudence." Apex Towing Co. v. Tolin, 41 S.W.3d 118, 122 (Tex. 2001) (citing S.V. v. R.V., 933 S.W.2d at 6); see also HECI Exploration Co. v. Neel, 982 S.W.2d 881, 886 (Tex. 1998). In HECI, we held that the discovery rule did not apply to royalty owners' claims for breach of a purported implied covenant to notify royalty owners of a potential claim against a third party for damage to the common reservoir. 982 S.W.2d at 886. In HECI, the plaintiffs, members of the Neel family, owned royalty interests under an oil and gas lease. Id. at 884. Their lessee and operator, HECI Exploration Company, discovered that AOP, a producer on an adjoining lease, had damaged the common reservoir by overproduction. Id. HECI sued AOP in 1988, and obtained monetary and injunctive relief in the trial court. Id. HECI and AOP eventually settled the suit and filed a release of judgment. Id. The Neels sued HECI in 1994, more than four years after damage to the reservoir had occurred. Id. Among other things, they alleged that HECI violated an implied covenant to notify them of the need to sue AOP. We assumed without deciding that such an implied covenant exists, but held that the statute of limitations barred the claim. Id. at 888. In concluding that the discovery rule did not apply, we focused on whether the injury underlying the Neels' failure-to-notify claim -- damage to the common reservoir -- was discoverable. 982 S.W.2d at 886-88. We reasoned that "when the Neels knew or should have known that they had a cause of action against AOP, they knew or should have known that HECI had not told them of that claim." Id. at 886.