If you could change one event from your past, would you? Helena congratulated herself for settling into her life quite nicely-until Brown reappeared as she tidied up after the Wizard of Oz themed party. A disturbing glitch had been discovered in the Watcher 22 program. Helena and the team are reunited to rescue clients unwittingly trapped in their past. With the merest whiff of a threat to national security, MI6 inevitably join the fray. Could the past be reinvented using Watcher 22? Was it time to hit the kill switch? There would always be consequences.