A Federation colony whose water supply was contaminated with tricyanate in 2366, a crisis secretly engineered by the collector Kivas Fajo in order to abduct Data.
Beta Agni II is a Federation colony world featured in the third-season Next Generation episode The Most Toys.
In 2366 the colony's underground water is found to be laced with tricyanate. The only substance able to neutralise it is hytritium, a compound too unstable to beam, and the trader Kivas Fajo is the one known source. While Data is ferrying the final load by shuttle from Fajo's ship, the shuttle explodes and he is believed lost. The Enterprise-D, pressed for time, goes on to the colony.
The treatment works, but La Forge and the others notice that the contamination is oddly easy to cure and does not occur naturally. They conclude that it was planted to create a need for hytritium, and return to find Fajo, who has been holding Data as the prize of his collection.