I've just been to see Wrath of the Titans, Gemma Arterton is credited very highly however I did not see her in a single scene?
Is she in the film?
If so where? If not why is she credited?
I know her character from Clash of the Titans was replaced by Rosamund Pike in 'Wrath' - are you confusing the two films?
According to Gemma's IMDb page, she is not in Wrath of the Titans
I haven't seen the newest film, so I cannot verify this though.
UPDATE (with SPOILER)
According to a review on the MovieBlog:
Gemma Arterton’s character Io, is no longer present as we learn she finally has died, a gift in some ways as Zeus granted her mortality. However her death did not come without a sense of happiness, as she bore Perseus’ son, Helios (John Bell), whom he now raises alone.
Every other site I visited claimed she was not in the film - so now I am doubly confused ;)
Gemma Arterton could not reprise her role as Io because she was filming Hansel and Gretel: Witch Hunter.