Living End

If the first triggered ability of suspend (the one that removes time counters) is countered, no time counter is removed. The ability will trigger again at the beginning of the card's owner's next upkeep.

If the spell requires any targets, those targets are chosen when the spell is finally cast, not when it's exiled.

Cards exiled with suspend are exiled face up.

When the last time counter is removed, the second triggered ability of suspend (the one that lets you cast the card) triggers. It doesn't matter why the last time counter was removed or what effect removed it.

A card with no mana cost can't be cast normally; you'll need a way to cast it for an alternative cost or without paying its mana cost, such as by suspending it.

If a card with no mana cost is given an alternative cost equal to its mana cost (by Snapcaster Mage, for example), that cost cannot be paid and the card cannot be cast this way.