Adrian Greenlough was the main protagonist in The Bridge. She was the daughter of Iris and Jercid Greenlough, the two Skippers of Holt Swiftstream. After her father was killed and the war begun, Adrian was filled with a deep hate for Holt Tidewater, and had the idea of a spy in the other Holt, thus sending her best friend, Violet Deepwater, into Holt Tidewater. Adrian was described as the brains behind her Holt, as was shown when she saved the remaining canoe from Iora Dirre and brought it back to be moored closer to the otters.
After Adrian met Iora, she found him seemingly "following her", and finally sneaked off to ask him what he needed. When he asked her for another meeting, she agreed, and eventually, through several meetings, Adrian found herself falling in love.
When Risra caught them meeting, Adrian swore him to secrecy, but was betrayed when he eventually told her mother they were meeting. Adrian and Iora ran away to Salamandastron, but returned back home after seeing that the mountain was deserted. Upon returning, Adrian and Iora tried to bring their Holts together, but were branded traitors until Risra stood up for them, sparking others to do the same.
In the end, Adrian and Iora are married.