“The Little Tiber,” said June sympathetically. “It flows with the power of the original Tiber, river of the empire. This is your last chance to back out, child. The mark of Achilles is a Greek blessing. You can’t retain it if you cross into Roman territory. The Tiber will wash it away.” Percy was too exhausted to understand all that, but he got the main point. “If I cross, I won’t have iron skin anymore?”
