Appellants’ defense, as set out in their answer, is that the negligence of Whitehurst was the sole proximate cause of plaintiffs’ damage and he is solely liable to the plaintiffs. Appellants’ position on appeal, as stated in their brief, is that the negligence of White-hurst was the primary cause of the explosion and fire which damaged the Messick house and he is primarily liable to plaintiffs. Their goal is complete exoneration or indemnity, not contribution under G.S. 1-240, but the ruling on this demurrer depends entirely upon the facts alleged in the answer.
Independently of G.S. 1-240, the law permits an adjudication in one action of primary and secondary liability between joint tort-feasors who are not in pari delicto. A defendant secondarily liable, when sued *531alone, may have the tort-feasor primarily liable brought into the action by alleging a cross action for indemnification against him. Clothing Store v. Ellis Stone & Co., 233 N.C. 126, 63 S.E. 2d 118; Bowman v. Greensboro, 190 N.C. 611, 130 S.E. 502.
Primary and secondary liability between defendants exists only when: (1) they are jointly and severally liable to the plaintiff, Lewis v. Insurance Co., 243 N.C. 55, 89 S.E. 2d 788; Hunsucker v. Chair Co., 237 N.C. 559, 75 S.E. 2d 768; Bost v. Metcalfe, 219 N.C. 607, 14 S.E. 2d 648; and (2) either (a) one has been passively negligent but is exposed to liability through the active negligence of the other or (b) one alone has done the act which produced the injury but the other is derivatively liable for the negligence of the former. Steele v. Hauling Co., 260 N.C. 486, 133 S.E. 2d 197; Newsome v. Surratt, 237 N.C. 297, 74 S.E. 2d 732; Clothing Store v. Ellis Stone & Co., supra; Johnson v. Asheville, 196 N.C. 550, 146 S.E. 229; Bowman v. Greensboro, supra; Guthrie v. Durham, 168 N.C. 573, 84 S.E. 859; Gregg v. Wilmington, 155 N.C. 18, 70 S.E. 1070; Dillon v. Raleigh, 124 N.C. 184, 32 S.E. 548; see also McBryde v. Lumber Co., 246 N.C. 415, 98 S.E. 2d 663.
The doctrine of primary-secondary liability cannot arise where an original defendant alleges that the one whom he would implead as a third-party defendant is solely liable to plaintiff. Greene v. Laboratories, Inc., 254 N.C. 680, 691, 120 S.E. 2d 82, 89; Walker v. Loyall, 210 N.C. 466, 187 S.E. 565; Bargeon v. Transportation Co., 196 N.C. 776, 147 S.E. 299; Ballinger v. Thomas, 195 N.C. 517, 142 S.E. 761. Obviously, if a plaintiff sues defendant A when the negligence of B is the sole proximate cause of plaintiff’s injuries and A has no derivative, or imputed, liability for the acts of B, A is not liable to the plaintiff and therefore not entitled to indemnity from B. If, on the other hand, A and B are in pari delicto, A’s remedy is against B for contribution; he may not have indemnity. Crowell v. Air Lines, 240 N.C. 20, 81 S.E. 2d 178; Newsome v. Surratt, supra; Taylor v. Construction Co., 195 N.C. 30, 114 S.E. 492; Doles v. R. R., 160 N.C. 318, 75 S.E. 722.
The rights of contribution and indemnity are mutually inconsistent; the former assumes joint fault, the latter only derivative fault. Although a defendant may plead inconsistent defenses, Woods v. Turner, 261 N.C. 643, 135 S.E. 2d 664; Freeman v. Thompson, 216 N.C. 484, 5 S.E. 2d 434, appellants here have not done so, nor does it appear that they could. According to the facts alleged in their answer, admitted to be true for the purpose of this demurrer, negligence of Whitehurst was the sole proximate cause of plaintiffs’ damage. Whitehurst had created a potentially dangerous situation of which he failed to give warning when he had a duty to warn Hamill. Williams v. Stores Co., Inc., 209 *532N.C. 591, 184 S.E. 496. If Whitehurst failed to give the warning, Hamill was guilty of no actionable negligence and plaintiffs could not recover against appellants, the only defendants whom they have sued. If, however, Whitehurst warned Hamill, appellants are solely responsible to plaintiffs. Between appellants and Whitehurst there existed no contractual relation from which Whitehurst’s negligence could be imputed to them; so they have no derivative liability for his acts.
One defendant may not substitute another party for himself by alleging the sole negligence of the other as the proximate cause of a plaintiff’s injuries. Since an original defendant may implead a third-party defendant only for the purpose of contribution or indemnity, and appellants have stated no cause of action for either against appellee, the ruling of the court below sustaining the demurrer is