Picard, Ro, Guinan, and Keiko are hurrying back from shore leave in a shuttlecraft to the Enterprise, which must answer a far-off distress signal. However, the shuttle is enveloped by a strange energy field, and while the four survive an emergency transport back to the Enterprise, they suddenly have the physical appearance and abilities of twelve-year-olds, although they are normal mentally.

While a very relaxed and playful Guinan attempts to convince Ro that their plight is not an unmitigated disaster, Picard attempts to resume command of the Enterprise as though nothing had happened. He quickly finds, however, that the reactions of those around him greatly reduce his ability to command, and on Beverly's suggestion hands command to Riker for the nonce. At the same time, Keiko has perhaps the most difficult time of all, having to help her husband and daughter deal with her changed circumstances.

Shortly after Picard considers his future options in the event that a cure is impossible, Beverly and Geordi deduce what has occurred. The field was a "molecular reversion field", which made the shuttle begin to deteriorate, and began to do the same to the crew, masking certain key genetic sequences from the transporter. Theoretically, then, sending them back through the transporter with the adult-level sequences included should cure them. However, that line of thought is temporarily put on hold when the Enterprise reaches orbit around Ligo 7, source of the distress signal.

They find no evidence of planetary distress, however; only interference. They prepare to investigate, when suddenly two Klingon birds of prey decloak and begin firing. They catch the Enterprise flatfooted, and the Enterprise is subdued without firing more than one shot. The boarders, independent Ferengi privateers in search of slave labor for mining down below, assume control of the ship in short order, although not before Riker orders computer command functions disabled.

Picard and the other children, meanwhile, are left on board in a classroom, thought to be harmless. They quickly work to lend what assistance they can, with Guinan and Ro moving down a service corridor to Engineering, Alexander luring a Ferengi out of the medical lab long enough to grab a couple of hyposprays, and Picard and Keiko using Alexander's remote- controlled car to sucker a Ferengi out of the transporter room, leaving them time to program the transporter and get some phasers.

With everything in place, all they need is to gain access to the command functions; and to do that, they need Riker to understand what's happening. Picard throws a tantrum at a nearby Ferengi, demanding to see Riker, his "father". The meeting goes well; although both speak in code, Riker appears to understand what they need. However, matters are complicated when DaiMon Lurin threatens Riker with the deaths of all the children unless he reactivated the computer and instructs Morta, another Ferengi, in its use.

Riker relents, but makes up explanations as he goes, confusing Morta. At the same time, he secretly gives Picard access to the command functions. The children move fast, slapping Ferengi right and left with communicators. The Ferengi, once "tagged", are beamed onto a transporter platform surrounded by a force field, and with their weapons deactivated. In short order, all but the two on the bridge are dealt with; and those two prove no difficulty for Picard and Riker to subdue themselves. With the crisis resolved, the children return to normal.