Temptation

S2, E12: For some time now, Jeremy has been acting increasingly weird. He insists that they keep returning to the past despite what his friends say. They are all too aware of the dangers inherent to returning to the past, namely, an increase in XANA's powers. Our heroes discover that XANA has tricked Jeremy into using Franz Hopper’s notes to build a machine which uses the return to the past process to increase XANA’s intellectual capacities tenfold.