Having been alive since the Great War, Keely has become extremely intelligent over the last two hundred years. For some time she has been working with Dr. Hildern on plant life in the wasteland. She traveled to Vault 22 to study the mysterious plant growth there and discovered the horrible creatures that were created. When the Courier meets her, she has been trapped in a cavern in the lowest level of the vault, the pest control area. Fixing the lift will make finding her easier (Keely will also make a comment on the lift if you have repaired it before saving her). Lower level players should take precautions as there are many giant mantises and spore plants in the caves, as well as a spore carrier savage leading up to Keely.
There Stands the Grass: Angela Williams asks the player to look for Keely while in Vault 22. Further on, Keely asks you to destroy the spores by igniting a gas leak she has made in the Pest Control section.
When finding Keely the second time on the 2nd floor, when talking to her ask "Has your research turned up anything interesting?". She will then reply "A few things here and there" eventually saying about "one of the chemicals secluded in the spore pods serves as a mild stimulant and as far as I can tell has no side affects when ingested by humans". She will then mention "There is a sample extract hidden around here somewhere" and William Farber at Camp McCarran might be interested. The spore pod extract is in fact food additive and is only referred to as "spore pod extract" by Keely & when delivering it to Farber saying "This spore pod extract from Keely should help with morale". He will reply he will test it immediately. Whether it works or not is unknown. The spore pod extract will stay in your inventory in misc items as food additive even after you have given it to Farber, but has no use.
In Vault 22 Expedition, entry 2, Keely mentions that she's logging the research on the computers she finds in the Vault 22, since her "Pip-Boy is on the fritz". This could indicate that Keely is a former resident of one of the Vault-TecVaults. It should also be noted that when the player meets her, she does not wear a Pip-Boy.
If the player walks into Vault 22 without having the quest There Stands the Grass activated, then Keely will not appear.