Born to Captain Gar Hatch of the airship Skatelow and an unknown deceased mother, Cinnaminson was born with the ability to see beyond the horizon and through darkness, as well as sense things that weren't seen. She was a secret navigator aboard her father's airship. Her over-protective father intended to keep her in that role for the rest of her life, but she fell in love with Penderrin Ohmsford during his voyage on their ship.
When the Skatelow was attacked by the assassin Aphasia Wye, only Cinnaminson survived while her father and two cousins were killed. She was forced to use her gift against Pen and search for him, but she found the courage to resist even when abused by the assassin and pretended not to see them. Eventually, she was rescued by Pen and his group and then joined him into the Inkrim, guiding him to the island of the Tanequil.
On the island she sacrificed herself so Pen could receive the darkwand. She became an aeriad of the Mother Tanequil, gaining true sight and freedom. Later, she is released by the Tanequil to inhabit her human body again so that she can live out her life with Pen, but she was only released after being exchanged with Pen's aunt, the former Ard Rhys Grianne Ohmsford.