The station is buzzing with the news that Kira has finally gone into labor. But Odo is surprisingly uninterested, having his own "baby" to deal with. The former Changeling has purchased an ailing infant Changeling from Quark, and, after Dr. Bashir heals the creature, begins the task of trying to teach his "child" to shapeshift. He is clearly displeased when Dr. Mora, the Bajoran scientist who "raised" Odo, arrives on the station to help.

Dr. Mora and Odo immediately clash over how to best raise the Changeling. Odo, still angry at the invasive methods Dr. Mora employed with him, hopes to reach the infant through encouragement. Mora, however, insists on probing and measuring the little creature, to Odo's horror and disgust. Unfortunately, Odo makes little progress using his own methods, and Mora is quick to point this out. Odo refuses to even consider the doctor's expertise until Sisko informs him that Starfleet Command wants Odo to establish communication with the Changeling as soon as possible — or lose the infant to Starfleet. Unwilling to give his "baby" up, Odo has no choice but to listen to his old nemesis.

Using Dr. Mora's equipment, Odo employs electric shocks — the same methods Mora used to teach him to shapeshift, to prod the changeling into holding several basic forms. As he experiences his first success, Odo tries to resist bonding with Mora, who, when he taught Odo, experienced the same sense of pride Odo now feels. However, they are both amazed when the creature forms a face with eyes, and uses them to peer at Odo.

The moment brings Odo and Mora together — especially when Mora admits to Odo that his caring seems to have helped him form a connection with the baby. Mora's support helps Odo to finally forgive him and actually thank him for helping him to become more than a simple lump of organic material. He invites Dr. Mora to celebrate their success with a glass of champagne, and Mora happily accepts. Odo winds up at Quark's, where he offers his heartfelt thanks to the Ferengi for changing his life. Unfortunately, the happy mood is shattered when Odo receives word that the little creature is dying.

Desperate, Odo begs Dr. Bashir to save his "child," but there is nothing that can be done. Odo then takes the goo into his hands and begs the little creature not to die. It does anyway, but as a final "gift" to its mentor, the infant changeling merges into Odo and restores his shapeshifting abilities.