When a new agent joins the NCIS team, there seems something strangely familiar about her, she is welcomed by everyone. But Is she really who she says she is? and will she bring danger to the team?

When a stranger appears in the TARDIS, with no explanation, the Doctor and Clara begin to ask questions. But the answers they find unearth a past the Doctor thought was long forgotten. Will the Doctor's façade, his mirror, finally crack?