[TOMT][TV series][1990s]A show where is one episode a grandma gets turned into gold and melted

I'm trying to find TV series in which grandmother of two heroes was turned into a gold statue and placed in a melting furnace of some sort, with a villain threating heroes to stay back, otherwise he'll melt their grandma. If I'm not mistaken, he followed through with that threat, and this is the only scene I remember from those series. Country of origin - don't know, possibly Australia or USA.