In the distant future mankind creates sentient cybertanks patterned on the human brain to help fight their alien enemies. Then, inexplicably, the humans vanished. They just went away. All that is left of the human empire are the cybertanks who, in their own way, keep the human civilization alive. With an intelligence based on the human psyche, the cybertanks continue to defend human space, but also perform scientific research, create art, form committees and ponder the universe.

These are the stories of one of the first cybertanks, known to his friends as "Old Guy." He has outlived most of his peers, and has had a wealth of experiences over his long life, but he is starting to slowly become obsolete. Join him and his comrades Double-Wide, Whiffle-Bat, Smoking Hole, Mondocat, and Bob, as they live and love and fight alien enemies such as the deadly Fructoids, the Yllg, and the fiendish Amok.