Saoirse Ronan will play Melanie Snyder, one of the remaining few humans left on Earth after an attack by parasitic aliens called Souls. This alien species can enter a human and essentially erase their personality from within. When Melanie is invaded by a Soul named Wanderer, he finds she won't surrender and starts to connect with her past life. Wanderer is said to be somewhat of a legend due to all the "hosts" he has invaded on several other planets.
Andrew Niccol is adapting the Stephenie Meyer novel. We reported in February that Susanna White (Nanny McPhee Returns) will direct The Host, although this new report indicates she has left the project. Andrew Niccol, who has directed Gattaca and the upcoming sci-fi thriller Now, may step in as the director. Andrew Niccol was originally set to direct The Host before leaving to make Now.
No production schedule was given for The Host.