He regulates the seasons and symbolizes Death and Rebirth in nature. Somewhat reluctantly, it appears.
Every summer, when his powers are strongest, when the flowers are blooming and the harvests are looking great, he collapses from heat exhaustion and dies. His soul flees to the Underworld where it’s nice and cool, leaving the world’s vegetation to fend for itself.
The resulting desolation causes much misery as plants decay and winter sets in. So his mourning wife ISHTAR nips down to the nether regions to rescue him. Which is such a complicated and arduous task that it always takes six months and by the time they reappear, spring is right on schedule.