On a rain-soaked morning I found an old golden retriever near a country bridge, holding a red leash in his mouth. He wouldn't come to me and he wouldn't let go. Every time I got close he pulled the leash back toward a drainage tunnel and stared into the dark. When I finally crawled in after it, I understood why he wouldn't leave. A smaller senior dog was tangled behind a fallen branch, and he had been standing guard over her the whole time. He didn't drop that leash until she was safe in my arms. They ride home together now, and there are two beds by the heater. They only ever use one.