“Castle” actors Seamus Dever and Stana Katic wrap up their Alternative Travel Project.

Watch for bonus appearances in this video by Nathan Fillion (Malcolm Reynolds in “Firefly” and “Serenity,” Richard Castle in “Castle”), Zachary Levi (“Chuck”), Alan Tudyk (Hoban “Wash” Washburne — the pilot — in “Firefly” and “Serenity”).