Since it is Valentine's Day, Open Road Films thought it would be the perfect opportunity to debut the latest trailer for The Host, the studio's adaptation of Stephenie Meyer's first post-Twilight novel. Saoirse Ronan portrays Melanie Stryder, a young woman who becomes one of the last humans on Earth to be infiltrated by aliens known as Souls, which completely take over a person's mind and body. Melanie refuses to succumb to her Soul known as Wanderer, and is willing to risk everything to protect those she loves. The studio has also unveiled a series of Valentine's Day cards that feature images from director Andrew Niccol's sci-fi romance, featuring cast members Saoirse Ronan, Jake Abel, and Max Irons. Take a look at the latest footage, then check out these V-Day cards and send them to the ones you love.