What's on tomorrow, May 18th?

8:00 - Nikita on CW, Shark Tank on ABC, Who do You Think You Are on NBC, all finales
9:00 - Degrassi on TeenNick, Grimm on NBC, Supernatural on CW, all finales
9:30 - Series premiere of Tron on Disney
10:00 - Whale Wars on Animal Planet, finale