Mother needs to be saved. A ransom needs to be paid. Brian is not a wealthy man - a burden shared with many fictional characters.
There are 8 episodes, logically numbered 0-7.
If you donate £15 to Lady Hovis' Ransom Fund this works out at just £1.87½ per episode.
You may, if you wish, donate more.
Alternatively, there are things to buy too, here.