Tony of Beverly's Plum shade is actually going to be both warm and cool. The coolness comes from the violet in the violet-red highlights, but the red in those highlights lends to the warmness of the color. The medium plum brown base is also a mix of cool (plum) and warm (brown). This is going to be a perfect color choice if you find that your skin tone is neutral, allowing you to wear both warm and cool tones.
Heather's color spotlight video for Plum: https://www.youtube.com/watch?v=iw2HXCuTkJA.
I hope this information has been helpful for you!