Ruby Lemere was the widow of Sergeant Ted Lemere of a K-9 bomb-sniffing unit for the Marine Corps. stationed in Afghanistan.
The day before Ted died, she received a video message from husband that indicated that he may have feared for his life from someone within his own unit.
Thus, she had NCIS investigate his death in case his death was foul play, being suspicious with the official report. Gibbs then asked her later whether Lemere had any enemies, she informed him that he didn't, although he did get into a fight with the doghandler nicknamed Pit six months prior.
Later, she received in the mail a talisman of unknown markings as a surprise, which she then delivered to NCIS directly, taking the bus and talking the bus driver into allowing Dex to come along because her car broke down and Dex, the in-transit member of the K-9 unit, and the former dog of Ted Lemere, wasn't allowed on the bus. She later arrived back at home with Gibbs, with her thanking Gibbs for even attempting to find the killer.
However, shortly after arriving back at home, Dex sensed an intruder in the house and attacked the intruder, causing her to call Gibbs for help. The intruder ultimately managed to get away, although Gibbs informed her that the intruder was not looking for her grandmother's ring, or any of the jewelry on her bed, indicating that the intruder was trying to search for the talisman that she had delivered to NCIS earlier.
After her husband's murderer was uncovered, she attended Ted's funeral, and also became Dex's legal owner, due to Dex entering permanent retirement due to being shot trying to avenge his handler's death.