Period is related to Morning. Morning is related to Alarm. Alarm is related to Bed. Bed is a type of Plot. 
Availability is a different concept from Lack. Lack is related to Missing. 
Period <--RelatedTo--> Morning <--RelatedTo--> Alarm <--RelatedTo--> Bed --IsA--> Plot 
Availability <--DistinctFrom--> Lack <--RelatedTo--> Missing 