The storyline is the culmination of events from Silver Surfer vol. 3, #34 (Feb. 1990) and the two-issue miniseries The Thanos Quest (Sept.- Oct. 1990).
Thanos mounts the six Infinity Gems (collected in the Thanos Quest limited series) on his left glove to form the titular Infinity Gauntlet. Each Gem grants its bearer complete mastery over one aspect of the multiverse: Time, Space, Mind, Soul, Reality, and Power. Now all-powerful and desperate to win the affections of Death, Thanos decides to offer the entity a gift of love by completing a task she had given him, erasing half the sentient life in the universe (including most of the X-Men, Daredevil, and the Fantastic Four), quite literally with a snap of his fingers.
Additional plotlines not addressed in the main story were featured in other books published during the same time period.