Underworld: Bloodline

Underworld Bloodline is a team-based multiplayer Half-Life mod based on the Sony action movie "Underworld". Rival clans of Vampires and Lycans (werewolves) fight each other while trying to secure a human that hides the power to make them invincible. The gameplay can be described as a mix between Hostage Rescue and Capture the Flag, but the maps are a lot larger and more complex, offering opportunities for a wide range of strategies, such as snipering from inside buildings or taking shortcuts by jumping between rooftops

When night falls, the battle begins. Unbeknownst to the human world, a centuries-old feud between warring Vampire and Lycan (werewolf) clans is escalating to a bloody and brutal climax. Armed with an arsenal of deadly weapons both ancient and modern, these mortal enemies are unrelenting in their quest to wipe each other from the face of the earth. You must choose on which side you will fight. Will you align yourself with the lithe and elegant Vampires, or the brutally powerful Lycans? Prowling the dark city streets and subway tunnels, you are compelled to destroy your ancient enemies while searching for The Hybrid -- a human with the power to make your people invincible.