In the present day, two young siblings discover a box filled with items from World War One, owned by a girl who is revealed to be their great, great grandmother, Harriet Knapton.

Louis and Sienna sit down with their dad and begin to look at the contents of the memory box, to find out all about their great, great grandma, Harriet.

Harriet's great-great-grandchildren discover objects from her life in these exclusive webisodes. This time, Louis and Sienna learn how to play capture the flag.

Louis and Sienna find out how to send secret signals using morse code.

Louis, Sienna and their dad read a letter from the front. Their dad explains it would have been censored - changed so people didn't know how bad it really was.

Louis and Sienna put what they've learnt to the test, with a map their dad has made.

Louis and Sienna get to the 'treasure'. It's not what they expected, but it's something very special.