Next week, dastardly Derek (Jamie Foreman) hires a hitman to terrorise Roxy Mitchell (Rita Simons), the mother of Jack's young daughter Amy - hoping to frighten her following their recent clashes.
Maslen told Inside Soap: "Jack's absolutely sickened when he discovers what Derek is planning.
"Jack may have used underhand tactics in the past to try and get custody of Amy, but this is taking things much too far. Jack would never forgive himself if anything bad happened to Roxy."
He elaborated: "The first Jack knows of this is when he calls round to the Mitchells' and Shirley tells him that Roxy didn't come home the night before.
"Jack's furious with Derek and also sick to his stomach at the thought something terrible could have happened to Roxy. He storms straight round to confront his brother - he just wants confirmation from Derek that Roxy is alive and well."
> Monday, February 20: Derek has dark plans for Roxy
> Tuesday, February 21: Derek embarks on revenge plan
> Thursday, February 23: Roxy receives a sinister visitor
> Friday, February 24: Shirley informs Jack that Roxy is missing