Tempus and his ghost army took over the Earth and enslaved all mankind. Isaac and his three friends used all existing records of the Ghostbusters in an attempt to defeat Tempus and the ghosts. Due to the use of a jerry rigged Ghost Bomb on Tempus,  a Time Slip occurred and caused Kylie Griffin and Isaac to swap places in the time stream, still giving the remaining Ghostbusters a chance to set things right.
After some struggling, Roland Jackson and Garrett Miller managed to bury a Proton Pack so that Kylie could use it to blast Tempus' future counterpart. Tempus' past counterpart was in the past attempting to open the Containment Unit. When Tempus' past and future counterparts were blasted, the Time Slip occurred again and the two Tempuses were merged into one. Tempus was then trapped and Kylie and Isaac were restored to their proper times.
Isaac is a pretty nice guy and he helped the Ghostbusters save Kylie and defeat Tempus.
- Although, he recognizes the legendary figures Kylie, Eduardo, and Roland, Isaac admits he isn't a history buff.
- ↑ Isaac (2009). Extreme Ghostbusters- Ghost Apocalyptic Future (1997) (DVD ts. 04:47-04:53). Sony Pictures Home Entertainment. Issac says: "My name is Isaac and I guess I'm from the future."
- ↑ Isaac (2009). Extreme Ghostbusters- Ghost Apocalyptic Future (1997) (DVD ts. 06:30-06:34). Sony Pictures Home Entertainment. Issac says: "All I know is one minute I'm throwing a Ghost Bomb at Tempus, the next thing I'm here."