Malice is missing his estranged daughter, Una, so Clemence creates the Unabot - a robot facsimile of the tyrant's daughter. Much to the real Una's horror, her metal doppelganger wastes no time wheedling her way into the gang, and Una finds herself on the verge of being replaced. But the Unabot has a hidden agenda - an evil hidden agenda - and Pax and the gang have to make a choice between trusting their human friend, or siding with the shiny but dangerous interloper.