When Krypton exploded, its smaller neighbor planet, Argo, was torn from its orbit, and its landscape was devastated by shock waves, earthquakes, and super tidal waves. After these cataclysmic events, the world began to slowly freeze from being too far from its sun, causing the deaths of the remaining inhabitants. The Argoans sent distress calls into space, but they were never answered.
Kala In-Ze, Argo's chief physician, placed herself and her family in cryonic stasis, in the hopes that they would survive until help came. Over time, ice gradually encroached on the cryonic cells, destroying all except the one holding Kala's teenaged daughter, Kara In-Ze.
Years later, Superman arrived in the star system in hopes of finding any survivors. He intercepted a distress signal, and traced it to the now frozen planet. It was a holographic message left behind by Kala In-Ze, as well as the cryonic tubes. He took the sole survivor, Kara, home with him.
During its final years as a habitable world, Argo was of a similar technological level to Earth in the 30th century.
In the comics Argo City was a city on Krypton and home of Jor-El's brother Zor-El, his wife Allura and daughter Kara. Argo City is also the capital of Argo—not to be confused with Argo City on Krypton, which was introduced in "For the Man Who Has Everything".
The fate of the planet was elaborated on in Evan Dorkin and Sarah Dyer's Superman Adventures #21. In it, it is revealed that Argo is a neighbor planet to Krypton, further from the sun Rao and on the opposite side. The destruction of Krypton created an aftershock for Argo, causing it to be thrown out of orbit into a new orbit along the outer rings, which greatly decreased solar radiation from Rao. Three years passed before Kala In-Ze froze her relatives in the pods. The other two pods contained Kara's uncle Del Im-Re and cousin Dar Im-Re. In the period between this, Argo's change was shown, terraforming from a verdant green world into an icy blue planet. Kara, her mother, uncle and cousin are shown gathering supplies and defending their home from the elements as well as renegade Argoans, the few survivors who have resorted to banditry to survive.
- "Far From Home" (Mentioned Only)