Simplify the following text for a Grade 10 native English-speaking person.
Original: Each of the four volume DVDs consisted of one disc and five episodes , with the exception of volume four , which had six episodes , and the boxed set contained all twenty-one episodes on five discs .
Simplified: Each of the four volume DVDs had one disc and five episodes , with the exception of volume four , which had six episodes , and the boxed set had all twenty-one episodes on five discs .