I won't give you a hook. I'll give you 10.
1. Musicians are considered the creators of the world. If music stopped, the world would collapse in cataclysmic disasters.
2. Paradise is portrayed as a family gathering where everyone gets along. Pious leaders un a tight ship among their noble houses, punishing harshly anyone who bickers internally. People speak of the ideal of peace, but practice hatred and war-mongering.
3. It is common belief that saints ,when they die, are reincarnated as domesticated animals. In this form they watch over and protect their human allies. Thus, pets are often named after saints and are always welcome inside churches. Animal-worship and ancestor-worship intermingle and are accepted by society.
4. The world craves heroes, and common people are often villains seeking to get heroes to do things for them. Most heroes adopt secret identities, feign their deaths, or engage in campaigns to ruin their own reputations (thereby saving their lives).
5. Kuo-toa are forming a floating biosphere in the sky made entirely of water. Glub-Alag, as the biosphere is called, is the precursor to a great spell technology which will cause the firmament of the sky to be broken and salt water to be sucked upward. This will create an environment in which the kuo-toa will be able to breathe on land. Then they'll be able to reach their goal of....mating with humans?....rescuing all fish in aquariams/pools?.....tracking their race's time capsule in the desert?
6. Once a great empire built a system of warning braziers in the mountains which could be lit in case of invasion. Today, the land is politically fractured. A threat is looming as has destroyed the nation to the far north (near the character's home). Only lighting the braziers will save the land, and this requires spywork. They need to convince the old Keepers of the Flame order to revive itself, get aide from the great eagles, acquire guides in each nation, etc. All the while the clock is ticking as the northern war machine advances.
7. Every person (and intelligent) creature in the world follows a code of honor (possibly varying types of codes, like justice, freedom, friendship, etc). It is common for people to give their opponents a "sporting chance." Every warrior is sworn to observe the dying will of an opponent. Even goblins, when outnumbering their foes, will offer the weakest looking character a chance for one-on-one battle with the goblin's champion to win their freedom, rather than waste life uneccesarily.
8. Several utopias exist on the world, each with a different idea of what utopia is: (1) Kirpah Nasmong is a gnomish utopia where every interaction is rife with puns, riddles, jokes, and double entendres. Every single person is lively and interesting. The dissenting opinion is valued so much that the gnomes don't get much done. It is said anyone bringing sarcasm into the gates will destroy the utopia. Another example is Sir Saroch's Kingdom - a utopia where all curses and disease has been eliminated. Indeed, no one ever gets ill in the kingdom, and no one even knows what a curse is. Without any disease, the population has exploded. However, the boundaries of the kingdom are finite, for only within them are the people disease free. Everything feels crowded and claustrophobic and houses are stacked upon each other.
9. A minority of people find arcane tattoos appearing on them overnight, the characters included. Gradually, the tattoos become a language. Several sages race to understand what the language means, but, with the government treating the "painted ones" as witches and cracking down on all attempts to understand the language, the sages are forced to employ thieves and adventurers to capture the painted ones from their prison camps. The secret is that the tattoos tell how to prevent an impending ecological disaster. They are the gift of a psychic race that killed itself by destroying its environment. The government accidentally released the race when exploring ways to open portals to hell in order to redeem a fallen angel who helped found the state.
10. Powerful monsters ravage the countryside. The trick to defeating them is learning that they thrive on being opposed. If one does not attack them, the monsters will go into fits of rage, digging themself into the ground. They will taunt the heroes as weakling and selfish mercenaries, but if one stays the course, the monsters eventually merge into the natural landscape, becoming simply parts of the scenery. The old hill where Grandpa faced the dragon, actually is the dragon. No longer monsters to be slain, but parts of the scenery to be navigated, the monsters loose their bite. The mark of a true hero then, is to conserve energy and to choose their fights carefully, knowing when not to fight.