Activision and Treyarch have released a preview trailer for the upcoming second map pack for Call of Duty: Black Ops, 'Escalation'.

First scheduled to release on Xbox 360 on May 3rd, Escalation contains four new multiplayer battlegrounds and one new Zombies mode map that includes new playable characters. If the previous 'First Strike' map pack is anything to go by, Escalation should follow on PlayStation 3 roughly one month afterwards and then hit PC another month later.