If there are mutual debts or demands between the plaintiff and defendant at the time of the commencement of the plaintiff's action, one debt or demand may be set off against the other.
N.H. Rev. Stat. Ann. § 515:7
Mutual Debts
Source
Official source: New Hampshire General Court. Reproduced from public-domain New Hampshire statutes; confirm against the official source for the current text. Not legal advice.