A motion for nonsuit (Code Civ. Proc., 581c) has the effect of a demurrer to the evidence: it concedes the truth of the facts presented by the plaintiff, but contends those facts are insufficient as a matter of law to establish a prima facie case. ( Alpert v. Villa Romano Homeowners Assn. (2000) 81 Cal.App.4th 1320, 1328.) A nonsuit after the conclusion of the plaintiff's opening statement is disfavored. "Granting a nonsuit at the close of an opening statement is particularly dangerous because counsel rarely present such an explicit, full, and unabridged version of the plaintiff's case that the court can be sufficiently confident of the impossibility of proof of a cause of action to abruptly terminate the litigation." ( Galanek v. Wismar, supra, 68 Cal.App.4th at p. 1424.) A nonsuit " 'can only be upheld on appeal if, after accepting all the asserted facts as true and indulging every legitimate inference in favor of plaintiff, it can be said those facts and inferences lead inexorably to the conclusion plaintiff cannot establish an essential element of its cause of action or has inadvertently established uncontrovertible proof of an affirmative defense. ' " (Ibid., quoting Abeyta v. Superior Court (1993) 17 Cal.App.4th 1037, 1041.) " ' "In determining whether the plaintiff's evidence is sufficient, the court may not weigh the evidence or consider the credibility of witnesses." ' " ( Khajavi, supra, 84 Cal.App.4th at p. 43.) Since a motion for nonsuit raises issues of law, an appellate court reviews the ruling on the motion de novo, employing the same standard employed by the trial court. ( Saunders v. Taylor (1996) 42 Cal.App.4th 1538, 1541-1542.) "Although a judgment of nonsuit must not be reversed if plaintiff's proof raises nothing more than speculation, suspicion, or conjecture, reversal is warranted if there is 'some substance to plaintiff's evidence upon which reasonable minds could differ . . . . " (Carson v. Facilities Development Co. (1984) 36 Cal.3d 830, 839, 206 Cal. Rptr. 136, 686 P.2d 656.)