Can a victim of the Dream spell's nightmare take another long rest immediately after the rest they were affected by Dream?

Question

The Dream spell states as part of its effect:

You can make the messenger appear monstrous and terrifying to the target. If you do, the messenger can deliver a message of no more than ten words and then the target must make a Wisdom saving throw. On a failed save, echoes of the phantasmal monstrosity spawn a nightmare that lasts the Duration of the target's sleep and prevents the target from gaining any benefit from that rest. In addition, when the target wakes up, it takes 3d6 psychic damage. (PHB, page 236)

If the victim is affected by Dream during a long rest, they don't gain the benefit of the long rest upon waking from their sleep (for example, a cleric won't recover spent spell slots).

Does this effect interact at all with being unable to benefit from more than one long rest in a 24-hour period? Could the victim wake from their Dream'd long rest (gaining no benefits) and immediately attempt to take another long rest to actually gain the benefits?

Answer 1

Yes.

You can only gain the benefits of a long rest once per 24 hours. If you don't gain the benefits for any reason (if it is interrupted by more than an hour of strenuous activity or, say, a bad Dream) then you can start a new one right away and try to gain the benefits, assuming that you don't get interrupted again.

From the Players Handbook

Long Rest

A long rest is a period of extended downtime, at least 8 hours long, during which a character sleeps for at least 6 hours and performs no more than 2 hours of light activity, such as reading, talking, eating, or standing watch. [note: this was errata'd in Sage Advice] If the rest is interrupted by a period of strenuous activity–at least 1 hour of walking, fighting, casting spells, or similar adventuring activity–the characters must begin the rest again to gain any benefit from it.

At the end of a long rest, a character regains all lost hit points. The character also regains spent Hit Dice, up to a number of dice equal to half of the character's total number of them (minimum of one die). For example, if a character has eight Hit Dice, he or she can regain four spent Hit Dice upon finishing a long rest.

A character can't benefit from more than one long rest in a 24-hour period, and a character must have at least 1 hit point at the start of the rest to gain its benefits. (PHB, page 186)

Note that it does not specify anywhere in the text including any errata changes that the character can't try again should the first rest not grant its benefits, it only specifies that they cannot gain the benefits more than once per 24 hour period.