A Washington state animal rescue organization found Tillie, an Irish Setter and Spaniel mix, watching over her dog friend Phoebe, a basset hound, in a cistern where she was trapped for over a week. Tillie would often run out and grab the attention of a community member who lived near the ravine where the cistern was located, but she would always return to watch over Phoebe.
After Tillie had gone out to notify the community member a few times, that person finally reported her to Vashon Island Pet Protection. They drove to the ravine and called out for Tillie, who barked to help them locate her.
Phoebe couldn't get out because the cistern was tall and Basset Hounds have small arms and legs. She could drink the water that was collected inside to sustain her until the rescuers came, though. Here's the rescue organization's Facebook post about the whole ordeal, which went viral: