Inclusion Criteria:

          -  Patients with presumed advanced-stage high grade serous ovarian, fallopian tube, or
             primary peritoneal carcinoma, based on the presence of carcinomatosis, and/or elevated
             cancer antigen (CA)125, and/or ovarian mass(es), or at the discretion of the treating
             physician

          -  Medically able to undergo primary cytoreductive surgery, at least 13 days and up to 28
             days after starting study drug, as determined by treating physician

          -  No prior therapy for high-grade serous ovarian, fallopian tube, or primary peritoneal
             carcinoma

          -  Patients must be able to swallow and tolerate oral medications and not have
             gastrointestinal illnesses that would preclude absorption of AZD1775 (e.g.
             uncontrolled nausea, vomiting, or diarrhea; malabsorption syndrome; ulcerative
             disease); Note: patient may not have a percutaneous endoscopic gastrostomy (PEG) tube
             or be receiving total parenteral nutrition (TPN)

          -  Absolute neutrophil count >= 1,500/mcL (within 7 days prior to initiation of therapy)

          -  Hemoglobin >= 9 gm/dL (within 7 days prior to initiation of therapy)

          -  Platelets >= 100,000/mcL (within 7 days prior to initiation of therapy)

          -  Total bilirubin =< 1.5 x upper limit of normal (ULN) (within 7 days prior to
             initiation of therapy)

          -  Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) =< 2.5 x upper
             limit of normal unless the liver is involved with tumor, in that case, AST and ALT
             must be =< 5 x upper limit of normal (within 7 days prior to initiation of therapy)

          -  Creatinine clearance > 50 mL/min (assessed by Cockcroft Gault estimation) and
             creatinine < 1.5 x ULN (within 7 days prior to initiation of therapy)

          -  Patients must have an Eastern Cooperative Oncology Group (ECOG) performance status of
             0 or 1

          -  Women of childbearing potential (WoCBP) may be included only if acceptable
             contraception is in place for two weeks before study entry, for the duration of the
             study and for 90 days after the last dose of AZD1775; WoCBP are defined as those who
             are not surgically sterile (ie, bilateral tubal ligation, bilateral oophorectomy, or
             complete hysterectomy) or postmenopausal (defined as 12 months with no menses without
             an alternative medical cause); acceptable methods of contraception include true
             abstinence in line with the preferred and usual lifestyle choice of the patient, tubal
             ligation, vasectomized partner, barrier methods (eg, cap plus spermicide, sponge plus
             spermicide, diaphragm plus spermicide, or male condom plus a spermicide), intrauterine
             device methods (eg, Copper T or Levonorgestrel-releasing intrauterine system), or
             hormonal methods (eg, any registered and marketed contraceptive agent that contains an
             estrogen and/or a progestational agent and that is administered via the oral,
             subcutaneous, transdermal, intrauterine, or intramuscular route as an implant, hormone
             shot or injection, combined pill, minipill or patch); all methods of contraception
             (with the exception of total abstinence) should be used in combination with the use of
             a condom by their male sexual partner for intercourse; periodic abstinence, the rhythm
             method, and the withdrawal method are not acceptable methods of birth control; all
             WoCBP must have a negative pregnancy test within 3 days prior to study the initiation
             of therapy; should a woman become pregnant or suspect she is pregnant while
             participating in this study, she should inform her treating physician immediately

          -  Women must not breast-feed while taking the study medications

          -  Patients must be able to understand and willing to sign an informed consent

        Exclusion Criteria:

          -  Prior treatment for ovarian, fallopian tube, or primary peritoneal cancer

          -  Current receipt of any other investigational agents or any additional anti-cancer
             agents for this or any other disease

          -  Known central nervous system (CNS) disease other than neurologically stable, treated
             brain metastases -- defined as metastasis having no evidence of progression or
             hemorrhage after treatment for at least 2 weeks

          -  Presence of other active cancers; patients with stage I cancer who have received
             definitive local treatment within the last 3 years, and whom are considered unlikely
             to recur, are eligible; all patients with previously treated in-situ carcinoma (i.e.,
             non-invasive) are eligible, as are patients with prior non-melanoma skin cancers

          -  Major surgical procedures =< 28 days of beginning study treatment, or minor surgical
             procedures =< 7 days (minor procedures done at time of laparoscopy are allowed); no
             waiting required following port-a-cath placement

          -  Significant symptom burden from presumed diagnosis including large volume ascites,
             pain requiring narcotic medication, or shortness of breath on exertion

          -  Myocardial infarction within 6 months before starting therapy, symptomatic congestive
             heart failure (New York Heart Association > class II), unstable angina, or unstable
             cardiac arrhythmia requiring medication

          -  Corrected QT interval (QTc) > 470 msec (as calculated by Fridericia correction
             formula) at study entry or congenital long QT syndrome

          -  Caution should be exercised when inhibitors or substrates of P-glycoprotein (P-gP),
             substrates of cytochrome P450 family 1 subfamily A member 2 (CYP1A2) with a narrow
             therapeutic range, sensitive substrates of cytochrome P450 family 2 subfamily C member
             19 (CYP2C19) or CYP2C19 substrates with a narrow therapeutic range are administered
             with AZD1775

          -  Herbal preparations are not allowed throughout the study; these herbal medications
             include, but are not limited to: St. John's wort, kava, ephedra (ma huang), gingko
             biloba, dehydroepiandrosterone (DHEA), yohimbe, saw palmetto, and ginseng; not willing
             to avoid grapefruit, grapefruit juices, grapefruit hybrids, Seville oranges, pummelos,
             and exotic citrus fruits from 14 days prior to the dose of study medication and during
             the entire study due to potential CYP3A4 interaction with the study medication; orange
             juice is allowed

          -  Any known hypersensitivity or contraindication to the components of study treatment

          -  Pregnant or breast-feeding

          -  As judged by the investigator, any evidence of severe or uncontrolled systemic
             diseases (e.g., severe hepatic impairment, interstitial lung disease [bilateral,
             diffuse, parenchymal lung disease], uncontrolled chronic renal diseases
             [glomerulonephritis, nephritic syndrome, Fanconi syndrome or renal tubular acidosis]),
             serious active infection or current unstable or uncompensated respiratory or cardiac
             conditions, or uncontrolled hypertension (blood pressure >= 140/90), active bleeding
             diatheses or active infection including hepatitis B, hepatitis C, and human
             immunodeficiency virus; screening for chronic conditions and infectious diseases is
             not required

          -  As judged by the investigator, the patient is unsuitable to participate in the study
             and the patient is unlikely to comply with study procedures, restrictions, and
             requirements

          -  Subject has had prescription or non-prescription drugs or other products known to be
             sensitive cytochrome P450 family 3 subfamily A member 4 (CYP3A4) substrates or CYP3A4
             substrates with a narrow therapeutic index, or to be moderate to strong inhibitors /
             inducers of CYP3A4 which cannot be discontinued two weeks prior to day 1 of dosing and
             withheld throughout the study until 2 weeks after the last dose of study drug;
             co-administration of aprepitant or fosaprepitant during this study is prohibited

          -  AZD1775 is an inhibitor of breast cancer resistance protein (BCRP).; the use of
             statins including atorvastatin are prohibited and patients should be moved on to
             non-breast cancer resistance protein (BCRP) alternatives