Past of the past - Le Plus-que-parfait
Bonjour Madame Cécile !
J’avais dû en racheter un nouveau après que Patrick avait cassé le mien.
This sentence is an example from a lesson. Here, plus-que-parfait has been used in both the verbs. Though the action of breaking took place first and then came the necessity to buy a new one.
Would you like to explain how these two cases can be both Le plus-que-parfait ? Here, one action precedes the other so can one be in Passé Composé and other in Le Plus-que-Parfait ?