True Time Travel

This spell instantly transports you and up to eight willing creatures of your choice that you can see within range, or a single object that you can see within range, to a point in time that you select. If you target an object, it must be able to fit entirely inside a 10-foot cube, and it can't be held or carried by an unwilling creature.

You must be specific with when year, month, day, time, and why you wish to time travel. The amount of time you wish to travel and the reason behind it determines whether you arrive there successfully. The GM rolls 1d100 and consults the table.

Amount of Time. "<1 minute in the past" means a any point in time that is in the past and is up to 10 minutes. If you do this in combat, the DM will ask you what you would have done differently. The DM then calculates what would have changed (ie. placement of monsters/players, damage taken/gained, and concentration held or broken.) If the DM requires you to make any ability checks or saving throws for while he is calculating combat, you have advantage on those rolls.

"<1 minute in the future" means a any point in time that is in the future and is up to 10 minutes. If you do this in combat, you are removed from combat until the chosen time. When you reappear, you are moved to that point in the turn order.

On Target. You and your group (or the target object) appear when you want to in the exact places you were.

Off Target. You and your group (or the target object) appear a random amount of time away from the destination. The amount of time off target is 1d10 × 1d10 percent of the time that was to be traveled. For example, if you tried to travel 100 years, landed off target, and rolled a 5 and 3 on the two d10s, then you would be off target by 15 percent, or 15 years off. The GM determines the direction off target randomly by flipping a coin and designating heads as the future, and tails as the past.

Similar Time. You and your group (or the target object) wind up in a different time that's visually or thematically similar to the target. If you are heading for a week ago when the sun was shining, for example, you might wind up a day where the sun was shining two months off target. Generally, you appear in the closest similar time, but since the spell has no range limit, you could conceivably wind up anywhere in time.

Mishap. The spell's unpredictable magic results in a difficult journey. Each traveling creature (or the target object) takes 3d10 force damage, and the GM re-rolls on the table to see where you wind up (multiple mishaps can occur, dealing damage each time). If a mishap occurs, the Time Piece breaks.