Filed by Plutonian Acquisition Corp II

Pursuant to Rule 425 under the Securities Act of 1933

and deemed filed pursuant to Rule 14a-12

 under the Securities Exchange Act of 1934

Subject Company: Plutonian Acquisition Corp II

(Commission File Number : 001-43249)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 8-K

Current Report

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

September 3, 2026

Date of Report (Date of earliest event reported)

Registrant’s telephone number, including area code: (646) 886-8892

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 7.01. Regulation FD Disclosure.

On September 3, 2026, Plutonian Acquisition Corp. II, a publicly traded special purpose acquisition company (“Plutonian II”), and NT1 Pty Ltd, an Australian mineral exploration company (“NT1””), announced that they have entered into an Agreement and Plan of Merger and Business Combination Agreement (the “BCA”), together with such other persons as are contemplated to become parties to the BCA as the “Purchaser” and “Merger Sub.” The transaction contemplated by the BCA is expected to result in a combined company listed on the New York Stock Exchange.

A copy of the press release is attached hereto as Exhibit 99.1 and is hereby incorporated into this Current Report on Form 8-K by reference. The press release and the information set forth therein shall not be deemed to be filed for purposes of Section 18 of the Exchange Act, or otherwise be subject to the liabilities of that section, nor shall it be deemed to be incorporated by reference in any filing under the Securities Act or the Exchange Act.

Additional Information About the Proposed Transaction and Where to Find It

The proposed transaction will be submitted to shareholders of Plutonian II and NT1 for their consideration. The combined company intends to file a registration statement on Form F-4 (the “Registration Statement”) with the SEC, which will include a proxy statement/prospectus to be distributed to Plutonian II’s shareholders in connection with Plutonian II’s solicitation for proxies for the vote by its shareholders in connection with the proposed transaction and other matters to be described in the Registration Statement, as well as the prospectus relating to the offer of the securities to be issued to NT1 shareholders in connection with the completion of the proposed transaction. After the Registration Statement has been filed and declared effective, a definitive proxy statement/prospectus and other relevant documents will be mailed to Plutonian II’s shareholders as of the record date established for voting on the proposed transaction. Before making any voting or investment decision, Plutonian II’s shareholders and other interested persons are advised to read, once available, the definitive proxy statement/prospectus, as well as other documents filed with the SEC by Plutonian II in connection with the proposed transaction, as these documents will contain important information about Plutonian II, NT1, and the proposed transaction. Shareholders may obtain a copy of the definitive proxy statement/prospectus, once available, as well as other documents filed by Plutonian II with the SEC, without charge, at the SEC’s website located at www.sec.gov.

Participants in Solicitation

Plutonian II, NT1, and their respective directors and executive officers may be deemed to be participants in the solicitation of proxies from Plutonian II’s shareholders in connection with the proposed transactions. Information regarding the persons who may, under SEC rules, be deemed participants in the solicitation of Plutonian II’s shareholders in connection with the proposed transactions will be set forth in the proxy statement/prospectus included in the Registration Statement. You can find more information about Plutonian II’s directors and executive officers in Plutonian II’s final prospectus related to its initial public offering dated April 28, 2026, and subsequent SEC reports. Additional information regarding the participants in the proxy solicitation and a description of their direct and indirect interests will be included in the proxy statement/prospectus when it becomes available. Shareholders, potential investors and other interested persons should read the proxy statement/prospectus carefully when it becomes available before making any voting or investment decisions. You may obtain free copies of these documents from the sources indicated above.

Forward-Looking Statements

This communication contains certain forward-looking statements within the meaning of the federal securities laws with respect to a proposed transaction among Plutonian II, NT1 and the other parties thereto. Forward-looking statements include information concerning the parties’ possible or assumed future results of operations, business strategies, competitive position, industry environment, potential growth opportunities, and the effects of regulation, including whether the transaction will generate returns for shareholders. These forward-looking statements are based on the parties’ management’s current expectations, projections, and beliefs, as well as a number of assumptions concerning future events. These forward-looking statements generally are identified by the words “believe,” “project,” “expect,” “anticipate,” “estimate,” “intend,” “strategy,” “future,” “opportunity,” “plan,” “may,” “should,” “will,” “would,” “will be,” “will continue,” “will likely result,” and similar expressions. Forward-looking statements are predictions, projections and other statements about future events that are based on current expectations and assumptions and, as a result, are subject to risks and uncertainties. Many factors could cause actual future events to differ materially from the forward-looking statements in this document. These risks, uncertainties, assumptions, and other important factors include, but are not limited to: (a) the occurrence of any event, change, or other circumstances that could give rise to the termination of negotiations and any subsequent definitive agreements with respect to the transaction; (b) the outcome of any legal proceedings that may be instituted against the parties, or others following the announcement of the transaction and any definitive agreements with respect thereto; (c) the inability to complete the transaction due to the failure to obtain the approval of the shareholders of Plutonian II or NT1 or to satisfy other conditions to closing, including the receipt of certain governmental and regulatory approvals; (d) changes to the proposed structure of the transaction that may be required or appropriate as a result of applicable laws or regulations or as a condition to obtaining regulatory approval of the transaction; (e) the ability to meet the applicable stock exchange listing standards following the consummation of the transaction; (f) the risk that the transaction disrupts current plans and operations of the parties or its subsidiaries as a result of the announcement and consummation of the transactions described herein; (g) the effect of the announcement or pendency of the transaction on the parties’ business relationships, operating results, and business generally; (h) the ability to recognize the anticipated benefits of the transaction, which may be affected by, among other things, competition, the ability of the surviving company to grow and manage growth profitably, maintain relationships with customers and suppliers and retain its management and key employees; (i) costs related to the transaction; (j) changes in applicable laws or regulations, including legal or regulatory developments (including, without limitation, accounting considerations) which could result in unforeseen delays in the timing of the transaction; (k) the possibility that the parties may be adversely affected by other economic, business, and/or competitive factors; and (l) other risks and uncertainties indicated from time to time in Plutonian II’s final prospectus related to its initial public offering dated April 28, 2026, including those under “Risk Factors” therein, and other documents filed or to be filed with the SEC by Plutonian II.

Copies are available on the SEC’s website at www.sec.gov. The foregoing list of factors is not exhaustive. You should carefully consider the foregoing factors and the other risks and uncertainties described in documents filed by Plutonian II or the surviving company from time to time with the SEC. These filings identify and address other important risks and uncertainties that could cause actual events and results to differ materially from those contained in the forward-looking statements. Forward-looking statements speak only as of the date they are made. Readers are cautioned not to put undue reliance on forward-looking statements, and the parties assume no obligation and do not intend to update or revise these forward-looking statements, whether as a result of new information, future events, or otherwise. No party gives any assurance that any party will achieve its expectations. 

No Offer or Solicitation

This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities, or a solicitation of any vote or approval, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. This communication is not, and under no circumstances is to be construed as, a prospectus, an advertisement or a public offering of the securities described herein in the United States or any other jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended, or exemptions therefrom. INVESTMENT IN ANY SECURITIES DESCRIBED HEREIN HAS NOT BEEN APPROVED BY THE SEC OR ANY OTHER REGULATORY AUTHORITY NOR HAS ANY AUTHORITY PASSED UPON OR ENDORSED THE MERITS OF THE OFFERING OR THE ACCURACY OR ADEQUACY OF THE INFORMATION CONTAINED HEREIN. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE. This press release is not, and under no circumstances is to be construed as, a prospectus, an advertisement or a public offering in any jurisdiction.

Item 9.01. Financial Statements and Exhibits. 

(d) Exhibits 

SIGNATURES 

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

ATTACHMENTS / EXHIBITS

PRESS RELEASE