Failure to give a unanimity instruction in a sex case in which multiple counts were alleged using identical charging language was prejudicial error. Addressing what it termed “a ‘perfect storm’ of prejudicial legal error,” the Third District held that a trial court had erred in refusing a defendant’s request for a unanimity instruction, and that not only did the error require reversal, it would likely require dismissal of all charges against the defendant. The defendant was charged with ten violations of Penal Code section 288(a), each involving the same victim and committed during the same time frame, and the prosecution used identical generic statutory language to describe each count and its associated allegation of substantial sexual conduct. Rather than providing a standard unanimity instruction as requested by the defense, the court instead gave the jury a modified version of CALJIC 4.71.5, which instructed the jury that it must unanimously agree that the prosecution proved beyond a reasonable doubt that the defendant committed all of the acts described by the alleged victim. The jury failed to follow this instruction, however, and convicted the defendant of only count one. The jury failed to reach a verdict on the associated substantial sexual conduct allegation, failed to reach a verdict on count two, and acquitted the defendant of the remaining charges. The appellate court ruled that the modified instruction had not complied with People v. Jones (1990) 51 Cal.3d 294, which only applies to situations in which there is no reasonable likelihood of juror disagreement as to particular acts, and which only permits the modified instruction to be given in addition to a standard unanimity instruction. The Third District further held that the appropriate standard of prejudice for failure to provide an appropriate unanimity instruction is whether the error was harmless beyond a reasonable doubt. Finally, the court held that if the defendant should enter a plea of once in jeopardy upon refiling of the charges, and make a nonfrivolous showing that he has already been placed in jeopardy for those charges, the unique circumstances of the case demand that the burden of proof be shifted to the prosecution to establish by a preponderance of evidence that the new charges involve different offenses than those of which the defendant was acquitted.