Great-grandfather was always right

My great-grandfather used to tell me, "Don't chase after sheep because you'll only end up with a arrow in your knee." I never quite understood his advice until one Easter, I was gardening with my best friend Valentina. All of a sudden, we found an underground tunnel! It was prickly and spooky sounds came from deep within. Valentina saw something interesting inside, jumped in, and I never saw her again. Great-granddaddy was right!