Unexpected is a synonym of Random. Random is related to Memory. 
Hour is related to Moment. Moment is related to Second. Second is related to Coat. Coat is related to Nice. 
Unexpected <--Synonym--> Random <--RelatedTo--> Memory 
Hour <--RelatedTo--> Moment <--RelatedTo--> Second <--RelatedTo--> Coat <--RelatedTo--> Nice 