In episode 6 of the Ushio to Tora anime, Asako and a boy she meets at the beach (Tatsuya) find themselves swallowed by some sort of giant sea serpent monstrosity. In the anime, Asako calls her grandparents' beach house using her cell phone, and that's how Ushio learns that she's in trouble.
But the manga was written back in the early '90s, before cell phones were commonplace (the anime has been relieved of some of the trappings of the '90s [much as Parasyte was] in the interest of appealing to modern audiences). How did this scene play out there? How did Ushio find out what had happened to Asako and Tatsuya?